diff --git a/gspread/client.py b/gspread/client.py
index 0255c598e..96f3d5914 100644
--- a/gspread/client.py
+++ b/gspread/client.py
@@ -39,7 +39,9 @@ def __init__(
     ) -> None:
         self.http_client = http_client(auth, session)
 
-    def set_timeout(self, timeout: Optional[Union[float, Tuple[float, float]]] = None):
+    def set_timeout(
+        self, timeout: Optional[Union[float, Tuple[float, float]]] = None
+    ) -> None:
         """How long to wait for the server to send
         data before giving up, as a float, or a ``(connect timeout,
         read timeout)`` tuple.
@@ -76,7 +78,7 @@ def list_spreadsheet_files(
         return files
 
     def _list_spreadsheet_files(
-        self, title=None, folder_id=None
+        self, title: Optional[str] = None, folder_id: Optional[str] = None
     ) -> Tuple[List[Dict[str, Any]], Response]:
         files = []
         page_token = ""
@@ -316,9 +318,9 @@ def copy(
                     continue
 
                 new_spreadsheet.share(
-                    email_address=p["emailAddress"],
-                    perm_type=p["type"],
-                    role=p["role"],
+                    email_address=str(p["emailAddress"]),
+                    perm_type=str(p["type"]),
+                    role=str(p["role"]),
                     notify=False,
                 )
 
diff --git a/gspread/http_client.py b/gspread/http_client.py
index 3a96c5bc8..7cc802dd2 100644
--- a/gspread/http_client.py
+++ b/gspread/http_client.py
@@ -284,7 +284,9 @@ def spreadsheets_sheets_copy_to(
         r = self.request("post", url, json=body)
         return r.json()
 
-    def fetch_sheet_metadata(self, id: str, params: Optional[ParamsType] = None) -> Any:
+    def fetch_sheet_metadata(
+        self, id: str, params: Optional[ParamsType] = None
+    ) -> Mapping[str, Any]:
         """Similar to :method spreadsheets_get:`gspread.http_client.spreadsheets_get`,
         get the spreadsheet form the API but by default **does not get the cells data**.
         It only retrieve the the metadata from the spreadsheet.
diff --git a/gspread/spreadsheet.py b/gspread/spreadsheet.py
index bad613d87..60158c394 100644
--- a/gspread/spreadsheet.py
+++ b/gspread/spreadsheet.py
@@ -7,10 +7,13 @@
 """
 
 import warnings
-from typing import Any, Dict, Union
+from typing import Any, Dict, Generator, Iterable, List, Mapping, Optional, Union
 
+from requests import Response
+
+from .cell import Cell
 from .exceptions import WorksheetNotFound
-from .http_client import HTTPClient
+from .http_client import HTTPClient, ParamsType
 from .urls import DRIVE_FILES_API_V3_URL, SPREADSHEET_DRIVE_URL
 from .utils import ExportFormat, finditem
 from .worksheet import Worksheet
@@ -19,37 +22,40 @@
 class Spreadsheet:
     """The class that represents a spreadsheet."""
 
-    def __init__(self, http_client: HTTPClient, properties: Dict[str, Any]):
+    def __init__(self, http_client: HTTPClient, properties: Dict[str, Union[str, Any]]):
         self.client = http_client
         self._properties = properties
 
         metadata = self.fetch_sheet_metadata()
+        import pprint
+
+        pprint.pprint(metadata)
         self._properties.update(metadata["properties"])
 
     @property
-    def id(self):
+    def id(self) -> str:
         """Spreadsheet ID."""
         return self._properties["id"]
 
     @property
-    def title(self):
+    def title(self) -> str:
         """Spreadsheet title."""
         return self._properties["title"]
 
     @property
-    def url(self):
+    def url(self) -> str:
         """Spreadsheet URL."""
         return SPREADSHEET_DRIVE_URL % self.id
 
     @property
-    def creationTime(self):
+    def creationTime(self) -> str:
         """Spreadsheet Creation time."""
         if "createdTime" not in self._properties:
             self.update_drive_metadata()
         return self._properties["createdTime"]
 
     @property
-    def lastUpdateTime(self):
+    def lastUpdateTime(self) -> str:
         """Spreadsheet last updated time.
         Only updated on initialisation.
         For actual last updated time, use get_lastUpdateTime()."""
@@ -62,31 +68,31 @@ def lastUpdateTime(self):
         return self._properties["modifiedTime"]
 
     @property
-    def timezone(self):
+    def timezone(self) -> str:
         """Spreadsheet timeZone"""
         return self._properties["timeZone"]
 
     @property
-    def locale(self):
+    def locale(self) -> str:
         """Spreadsheet locale"""
         return self._properties["locale"]
 
     @property
-    def sheet1(self):
+    def sheet1(self) -> Worksheet:
         """Shortcut property for getting the first worksheet."""
         return self.get_worksheet(0)
 
-    def __iter__(self):
+    def __iter__(self) -> Generator[Worksheet, None, None]:
         yield from self.worksheets()
 
-    def __repr__(self):
+    def __repr__(self) -> str:
         return "<{} {} id:{}>".format(
             self.__class__.__name__,
             repr(self.title),
             self.id,
         )
 
-    def batch_update(self, body):
+    def batch_update(self, body: Mapping[str, Any]) -> Any:
         """Lower-level method that directly calls `spreadsheets/<ID>:batchUpdate <https://developers.google.com/sheets/api/reference/rest/v4/spreadsheets/batchUpdate>`_.
 
         :param dict body: `Batch Update Request body <https://developers.google.com/sheets/api/reference/rest/v4/spreadsheets/batchUpdate#request-body>`_.
@@ -97,7 +103,9 @@ def batch_update(self, body):
         """
         return self.client.batch_update(self.id, body)
 
-    def values_append(self, range, params, body):
+    def values_append(
+        self, range: str, params: ParamsType, body: Mapping[str, Any]
+    ) -> Any:
         """Lower-level method that directly calls `spreadsheets/<ID>/values:append <https://developers.google.com/sheets/api/reference/rest/v4/spreadsheets.values/append>`_.
 
         :param str range: The `A1 notation <https://developers.google.com/sheets/api/guides/concepts#a1_notation>`_
@@ -111,7 +119,7 @@ def values_append(self, range, params, body):
         """
         return self.client.values_append(self.id, range, params, body)
 
-    def values_clear(self, range):
+    def values_clear(self, range: str) -> Any:
         """Lower-level method that directly calls `spreadsheets/<ID>/values:clear <https://developers.google.com/sheets/api/reference/rest/v4/spreadsheets.values/clear>`_.
 
         :param str range: The `A1 notation <https://developers.google.com/sheets/api/guides/concepts#a1_notation>`_ of the values to clear.
@@ -122,7 +130,11 @@ def values_clear(self, range):
         """
         return self.client.values_clear(self.id, range)
 
-    def values_batch_clear(self, params=None, body=None):
+    def values_batch_clear(
+        self,
+        params: Optional[ParamsType] = None,
+        body: Optional[Mapping[str, Any]] = None,
+    ) -> Any:
         """Lower-level method that directly calls `spreadsheets/<ID>/values:batchClear`
 
         :param dict params: (optional) `Values Batch Clear Query parameters <https://developers.google.com/sheets/api/reference/rest/v4/spreadsheets.values/batchClear#path-parameters>`_.
@@ -131,7 +143,7 @@ def values_batch_clear(self, params=None, body=None):
         """
         return self.client.values_batch_clear(self.id, params, body)
 
-    def values_get(self, range, params=None):
+    def values_get(self, range: str, params: Optional[ParamsType] = None) -> Any:
         """Lower-level method that directly calls `GET spreadsheets/<ID>/values/<range> <https://developers.google.com/sheets/api/reference/rest/v4/spreadsheets.values/get>`_.
 
         :param str range: The `A1 notation <https://developers.google.com/sheets/api/guides/concepts#a1_notation>`_ of the values to retrieve.
@@ -143,7 +155,9 @@ def values_get(self, range, params=None):
         """
         return self.client.values_get(self.id, range, params=params)
 
-    def values_batch_get(self, ranges, params=None):
+    def values_batch_get(
+        self, ranges: List[str], params: Optional[ParamsType] = None
+    ) -> Any:
         """Lower-level method that directly calls `spreadsheets/<ID>/values:batchGet <https://developers.google.com/sheets/api/reference/rest/v4/spreadsheets.values/batchGet>`_.
 
         :param list ranges: List of ranges in the `A1 notation <https://developers.google.com/sheets/api/guides/concepts#a1_notation>`_ of the values to retrieve.
@@ -153,7 +167,12 @@ def values_batch_get(self, ranges, params=None):
         """
         return self.client.values_batch_get(self.id, ranges, params=params)
 
-    def values_update(self, range, params=None, body=None):
+    def values_update(
+        self,
+        range: str,
+        params: Optional[ParamsType] = None,
+        body: Optional[Mapping[str, Any]] = None,
+    ) -> Any:
         """Lower-level method that directly calls `PUT spreadsheets/<ID>/values/<range> <https://developers.google.com/sheets/api/reference/rest/v4/spreadsheets.values/update>`_.
 
         :param str range: The `A1 notation <https://developers.google.com/sheets/api/guides/concepts#a1_notation>`_ of the values to update.
@@ -178,7 +197,7 @@ def values_update(self, range, params=None, body=None):
         """
         return self.client.values_update(self.id, range, params=params, body=body)
 
-    def values_batch_update(self, body=None):
+    def values_batch_update(self, body: Optional[Mapping[str, Any]] = None) -> Any:
         """Lower-level method that directly calls `spreadsheets/<ID>/values:batchUpdate <https://developers.google.com/sheets/api/reference/rest/v4/spreadsheets.values/batchUpdate>`_.
 
         :param dict body: (optional) `Values Batch Update Request body <https://developers.google.com/sheets/api/reference/rest/v4/spreadsheets.values/batchUpdate#request-body>`_.
@@ -187,17 +206,21 @@ def values_batch_update(self, body=None):
         """
         return self.client.values_batch_update(self.id, body=body)
 
-    def _spreadsheets_get(self, params=None):
+    def _spreadsheets_get(self, params: Optional[ParamsType] = None) -> Any:
         """A method stub that directly calls `spreadsheets.get <https://developers.google.com/sheets/api/reference/rest/v4/spreadsheets/get>`_."""
         return self.client.spreadsheets_get(self.id, params=params)
 
-    def _spreadsheets_sheets_copy_to(self, sheet_id, destination_spreadsheet_id):
+    def _spreadsheets_sheets_copy_to(
+        self, sheet_id: int, destination_spreadsheet_id: str
+    ) -> Any:
         """Lower-level method that directly calls `spreadsheets.sheets.copyTo <https://developers.google.com/sheets/api/reference/rest/v4/spreadsheets.sheets/copyTo>`_."""
         return self.client.spreadsheets_sheets_copy_to(
             self.id, sheet_id, destination_spreadsheet_id
         )
 
-    def fetch_sheet_metadata(self, params=None):
+    def fetch_sheet_metadata(
+        self, params: Optional[ParamsType] = None
+    ) -> Mapping[str, Any]:
         """Similar to :method spreadsheets_get:`gspread.http_client.spreadsheets_get`,
         get the spreadsheet form the API but by default **does not get the cells data**.
         It only retrieve the the metadata from the spreadsheet.
@@ -209,7 +232,7 @@ def fetch_sheet_metadata(self, params=None):
         """
         return self.client.fetch_sheet_metadata(self.id, params=params)
 
-    def get_worksheet(self, index):
+    def get_worksheet(self, index: int) -> Worksheet:
         """Returns a worksheet with specified `index`.
 
         :param index: An index of a worksheet. Indexes start from zero.
@@ -233,7 +256,7 @@ def get_worksheet(self, index):
         except (KeyError, IndexError):
             raise WorksheetNotFound("index {} not found".format(index))
 
-    def get_worksheet_by_id(self, id: Union[str, int]):
+    def get_worksheet_by_id(self, id: Union[str, int]) -> Worksheet:
         """Returns a worksheet with specified `worksheet id`.
 
         :param id: The id of a worksheet. it can be seen in the url as the value of the parameter 'gid'.
@@ -264,7 +287,7 @@ def get_worksheet_by_id(self, id: Union[str, int]):
         except (StopIteration, KeyError):
             raise WorksheetNotFound("id {} not found".format(worksheet_id_int))
 
-    def worksheets(self, exclude_hidden: bool = False):
+    def worksheets(self, exclude_hidden: bool = False) -> List[Worksheet]:
         """Returns a list of all :class:`worksheets <gspread.worksheet.Worksheet>`
         in a spreadsheet.
 
@@ -284,7 +307,7 @@ def worksheets(self, exclude_hidden: bool = False):
             worksheets = [w for w in worksheets if not w.isSheetHidden]
         return worksheets
 
-    def worksheet(self, title):
+    def worksheet(self, title: str) -> Worksheet:
         """Returns a worksheet with specified `title`.
 
         :param title: A title of a worksheet. If there're multiple
@@ -312,7 +335,9 @@ def worksheet(self, title):
         except (StopIteration, KeyError):
             raise WorksheetNotFound(title)
 
-    def add_worksheet(self, title, rows, cols, index=None):
+    def add_worksheet(
+        self, title: str, rows: int, cols: int, index: Optional[int] = None
+    ) -> Worksheet:
         """Adds a new worksheet to a spreadsheet.
 
         :param title: A title of a new worksheet.
@@ -326,7 +351,9 @@ def add_worksheet(self, title, rows, cols, index=None):
 
         :returns: a newly created :class:`worksheets <gspread.worksheet.Worksheet>`.
         """
-        body = {
+        body: Dict[
+            str, List[Dict[str, Dict[str, Dict[str, Union[str, int, Dict[str, int]]]]]]
+        ] = {
             "requests": [
                 {
                     "addSheet": {
@@ -354,11 +381,11 @@ def add_worksheet(self, title, rows, cols, index=None):
 
     def duplicate_sheet(
         self,
-        source_sheet_id,
-        insert_sheet_index=None,
-        new_sheet_id=None,
-        new_sheet_name=None,
-    ):
+        source_sheet_id: int,
+        insert_sheet_index: Optional[int] = None,
+        new_sheet_id: Optional[int] = None,
+        new_sheet_name: Optional[str] = None,
+    ) -> Worksheet:
         """Duplicates the contents of a sheet.
 
         :param int source_sheet_id: The sheet ID to duplicate.
@@ -388,7 +415,7 @@ def duplicate_sheet(
             new_sheet_name=new_sheet_name,
         )
 
-    def del_worksheet(self, worksheet):
+    def del_worksheet(self, worksheet: Worksheet) -> Any:
         """Deletes a worksheet from a spreadsheet.
 
         :param worksheet: The worksheet to be deleted.
@@ -398,7 +425,7 @@ def del_worksheet(self, worksheet):
 
         return self.client.batch_update(self.id, body)
 
-    def del_worksheet_by_id(self, worksheet_id: Union[str, int]):
+    def del_worksheet_by_id(self, worksheet_id: Union[str, int]) -> Any:
         """
         Deletes a Worksheet by id
         """
@@ -411,7 +438,9 @@ def del_worksheet_by_id(self, worksheet_id: Union[str, int]):
 
         return self.client.batch_update(self.id, body)
 
-    def reorder_worksheets(self, worksheets_in_desired_order):
+    def reorder_worksheets(
+        self, worksheets_in_desired_order: Iterable[Worksheet]
+    ) -> Any:
         """Updates the ``index`` property of each Worksheet to reflect
         its index in the provided sequence of Worksheets.
 
@@ -448,13 +477,13 @@ def reorder_worksheets(self, worksheets_in_desired_order):
 
     def share(
         self,
-        email_address,
-        perm_type,
-        role,
-        notify=True,
-        email_message=None,
-        with_link=False,
-    ):
+        email_address: str,
+        perm_type: str,
+        role: str,
+        notify: bool = True,
+        email_message: Optional[str] = None,
+        with_link: bool = False,
+    ) -> Response:
         """Share the spreadsheet with other accounts.
 
         :param email_address: user or group e-mail address, domain name
@@ -492,7 +521,7 @@ def share(
             with_link=with_link,
         )
 
-    def export(self, format=ExportFormat.PDF):
+    def export(self, format: ExportFormat = ExportFormat.PDF) -> bytes:
         """Export the spreadsheet in the given format.
 
         :param str file_id: A key of a spreadsheet to export
@@ -517,11 +546,11 @@ def export(self, format=ExportFormat.PDF):
         """
         return self.client.export(self.id, format)
 
-    def list_permissions(self):
+    def list_permissions(self) -> List[Dict[str, Union[str, bool]]]:
         """Lists the spreadsheet's permissions."""
         return self.client.list_permissions(self.id)
 
-    def remove_permissions(self, value, role="any"):
+    def remove_permissions(self, value: str, role: str = "any") -> List[str]:
         """Remove permissions from a user or domain.
 
         :param value: User or domain to remove permissions from
@@ -542,8 +571,8 @@ def remove_permissions(self, value, role="any"):
 
         key = "emailAddress" if "@" in value else "domain"
 
-        filtered_id_list = [
-            p["id"]
+        filtered_id_list: List[str] = [
+            str(p["id"])
             for p in permission_list
             if p.get(key) == value and (p["role"] == role or role == "any")
         ]
@@ -553,7 +582,7 @@ def remove_permissions(self, value, role="any"):
 
         return filtered_id_list
 
-    def transfer_ownership(self, permission_id):
+    def transfer_ownership(self, permission_id: str) -> Response:
         """Transfer the ownership of this file to a new user.
 
         It is necessary to first create the permission with the new owner's email address,
@@ -581,7 +610,7 @@ def transfer_ownership(self, permission_id):
 
         return self.client.request("patch", url, json=payload)
 
-    def accept_ownership(self, permission_id):
+    def accept_ownership(self, permission_id: str) -> Response:
         """Accept the pending ownership request on that file.
 
         It is necessary to edit the permission with the pending ownership.
@@ -601,13 +630,13 @@ def accept_ownership(self, permission_id):
             "role": "owner",
         }
 
-        params = {
+        params: ParamsType = {
             "transferOwnership": True,
         }
 
         return self.client.request("patch", url, json=payload, params=params)
 
-    def named_range(self, named_range):
+    def named_range(self, named_range: str) -> List[Cell]:
         """return a list of :class:`gspread.cell.Cell` objects from
         the specified named range.
 
@@ -619,13 +648,13 @@ def named_range(self, named_range):
         # This is only here to provide better user experience.
         return self.sheet1.range(named_range)
 
-    def list_named_ranges(self):
+    def list_named_ranges(self) -> List[Any]:
         """Lists the spreadsheet's named ranges."""
         return self.fetch_sheet_metadata(params={"fields": "namedRanges"}).get(
             "namedRanges", []
         )
 
-    def update_title(self, title):
+    def update_title(self, title: str) -> Any:
         """Renames the spreadsheet.
 
         :param str title: A new title.
@@ -645,7 +674,7 @@ def update_title(self, title):
         self._properties["title"] = title
         return res
 
-    def update_timezone(self, timezone):
+    def update_timezone(self, timezone: str) -> Any:
         """Updates the current spreadsheet timezone.
         Can be any timezone in CLDR format such as "America/New_York"
         or a custom time zone such as GMT-07:00.
@@ -666,7 +695,7 @@ def update_timezone(self, timezone):
         self._properties["timeZone"] = timezone
         return res
 
-    def update_locale(self, locale):
+    def update_locale(self, locale: str) -> Any:
         """Update the locale of the spreadsheet.
         Can be any of the ISO 639-1 language codes, such as: de, fr, en, ...
         Or an ISO 639-2 if no ISO 639-1 exists.
@@ -692,9 +721,9 @@ def update_locale(self, locale):
         self._properties["locale"] = locale
         return res
 
-    def list_protected_ranges(self, sheetid):
+    def list_protected_ranges(self, sheetid: int) -> List[Any]:
         """Lists the spreadsheet's protected named ranges"""
-        sheets = self.fetch_sheet_metadata(
+        sheets: List[Mapping[str, Any]] = self.fetch_sheet_metadata(
             params={"fields": "sheets.properties,sheets.protectedRanges"}
         )["sheets"]
 
diff --git a/gspread/utils.py b/gspread/utils.py
index 59d25818d..02aa12f6d 100644
--- a/gspread/utils.py
+++ b/gspread/utils.py
@@ -244,7 +244,7 @@ def numericise(
 
 
 def numericise_all(
-    values: List[Optional[AnyStr]],
+    values: List[AnyStr],
     empty2zero: bool = False,
     default_blank: Any = "",
     allow_underscores_in_numeric_literals: bool = False,
@@ -521,7 +521,7 @@ def column_letter_to_index(column: str) -> int:
     return index
 
 
-def cast_to_a1_notation(method: Callable[..., Any]) -> Callable[..., Any]:
+def cast_to_a1_notation(method: Callable[..., T]) -> Callable[..., T]:
     """Decorator function casts wrapped arguments to A1 notation in range
     method calls.
     """
@@ -709,7 +709,12 @@ def is_scalar(x: Any) -> bool:
     return isinstance(x, str) or not isinstance(x, Sequence)
 
 
-def combined_merge_values(worksheet_metadata, values, start_row_index, start_col_index):
+def combined_merge_values(
+    worksheet_metadata: Mapping[str, Any],
+    values: List[List[Any]],
+    start_row_index: int,
+    start_col_index: int,
+) -> List[List[Any]]:
     """For each merged region, replace all values with the value of the top-left cell of the region.
     e.g., replaces
     [
@@ -733,6 +738,9 @@ def combined_merge_values(worksheet_metadata, values, start_row_index, start_col
 
     :param start_col_index: The index of the first column of the values in the worksheet.
         e.g., if the values are in columns C-E, this should be 2.
+
+    :returns: matrix of values with merged coordinates filled according to top-left value
+    :rtype: list(list(any))
     """
     merges = worksheet_metadata.get("merges", [])
     # each merge has "startRowIndex", "endRowIndex", "startColumnIndex", "endColumnIndex
diff --git a/gspread/worksheet.py b/gspread/worksheet.py
index 5710a4f83..dd1b2ad73 100644
--- a/gspread/worksheet.py
+++ b/gspread/worksheet.py
@@ -114,7 +114,7 @@ class ValueRange(list):
        It will be instantiated using the response from the sheet API.
     """
 
-    _json: MutableMapping[str, Any] = {}
+    _json: MutableMapping[str, str] = {}
 
     @classmethod
     def from_json(cls: Type[ValueRangeType], json: Mapping[str, Any]) -> ValueRangeType:
@@ -449,7 +449,7 @@ def get_values(
         maintain_size: bool = False,
         pad_values: bool = True,
         return_type: GridRangeType = GridRangeType.ListOfLists,
-    ) -> List[List[T]]:
+    ) -> Union[ValueRange, List[List[Any]]]:
         """Alias for :meth:`~gspread.worksheet.Worksheet.get`...
 
         with ``return_type`` set to ``List[List[Any]]``
@@ -477,7 +477,7 @@ def get_all_values(
         maintain_size: bool = False,
         pad_values: bool = True,
         return_type: GridRangeType = GridRangeType.ListOfLists,
-    ) -> List[List[T]]:
+    ) -> Union[ValueRange, List[List[Any]]]:
         """Alias to :meth:`~gspread.worksheet.Worksheet.get_values`"""
         return self.get_values(
             range_name=range_name,
@@ -492,13 +492,13 @@ def get_all_values(
 
     def get_all_records(
         self,
-        head=1,
-        expected_headers=None,
-        value_render_option=None,
-        default_blank="",
-        numericise_ignore=[],
-        allow_underscores_in_numeric_literals=False,
-        empty2zero=False,
+        head: int = 1,
+        expected_headers: Optional[List[str]] = None,
+        value_render_option: Optional[ValueRenderOption] = None,
+        default_blank: str = "",
+        numericise_ignore: Iterable[Union[str, int]] = [],
+        allow_underscores_in_numeric_literals: bool = False,
+        empty2zero: bool = False,
     ) -> List[Dict[str, Union[int, float, str]]]:
         """Returns a list of dictionaries, all of them having the contents of
         the spreadsheet with the head row as keys and each of these
@@ -598,7 +598,7 @@ def get_all_records(
                     empty2zero,
                     default_blank,
                     allow_underscores_in_numeric_literals,
-                    numericise_ignore,
+                    numericise_ignore,  # type: ignore
                 )
                 for row in values
             ]
@@ -616,7 +616,7 @@ def row_values(
         major_dimension: Optional[Dimension] = None,
         value_render_option: Optional[ValueRenderOption] = None,
         date_time_render_option: Optional[DateTimeOption] = None,
-    ) -> List[Optional[Union[int, float, str]]]:
+    ) -> List[str]:
         """Returns a list of all values in a `row`.
 
         Empty cells in this list will be rendered as :const:`None`.
@@ -826,7 +826,7 @@ def get(
         maintain_size: bool = False,
         pad_values: bool = False,
         return_type: GridRangeType = GridRangeType.ValueRange,
-    ) -> Union[ValueRange, List[List[Any]]]:
+    ) -> Union[ValueRange, List[List[str]]]:
         """Reads values of a single range or a cell of a sheet.
 
         Returns a ValueRange (list of lists) containing all values from a specified range or cell
@@ -2091,12 +2091,14 @@ def add_protected_range(
                             "description": description,
                             "warningOnly": warning_only,
                             "requestingUserCanEdit": requesting_user_can_edit,
-                            "editors": None
-                            if warning_only
-                            else {
-                                "users": editor_users_emails,
-                                "groups": editor_groups_emails,
-                            },
+                            "editors": (
+                                None
+                                if warning_only
+                                else {
+                                    "users": editor_users_emails,
+                                    "groups": editor_groups_emails,
+                                }
+                            ),
                         }
                     }
                 }
@@ -2395,7 +2397,7 @@ def freeze(
         return res
 
     @cast_to_a1_notation
-    def set_basic_filter(self, name: Optional[str] = None):
+    def set_basic_filter(self, name: Optional[str] = None) -> Any:
         """Add a basic filter to the worksheet. If a range or boundaries
         are passed, the filter will be limited to the given range.
 
@@ -2538,7 +2540,7 @@ def copy_to(
         )
 
     @cast_to_a1_notation
-    def merge_cells(self, name: str, merge_type: str = MergeType.merge_all):
+    def merge_cells(self, name: str, merge_type: str = MergeType.merge_all) -> Any:
         """Merge cells.
 
         :param str name: Range name in A1 notation, e.g. 'A1:A5'.