From a7136d7890d8fbd439719bccfbc6c7b4ede70e9d Mon Sep 17 00:00:00 2001
From: Isuru Fernando <isuruf@gmail.com>
Date: Mon, 22 Jan 2024 21:38:36 -0600
Subject: [PATCH 1/2] Raise error on wrong number of arguments to Function

---
 symengine/lib/symengine_wrapper.in.pyx | 11 +++++++++--
 symengine/tests/test_functions.py      |  9 +++++++++
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/symengine/lib/symengine_wrapper.in.pyx b/symengine/lib/symengine_wrapper.in.pyx
index 8974b7d9..4fdc0f9c 100644
--- a/symengine/lib/symengine_wrapper.in.pyx
+++ b/symengine/lib/symengine_wrapper.in.pyx
@@ -2412,8 +2412,15 @@ class Pow(Expr):
 class Function(Expr):
 
     def __new__(cls, *args, **kwargs):
-        if cls == Function and len(args) == 1:
-            return UndefFunction(args[0])
+        if cls == Function:
+            nargs = len(args)
+            if nargs == 0:
+                raise TypeError("Required at least one argument to Function")
+            elif nargs == 1:
+                return UndefFunction(args[0])
+            elif nargs > 1:
+                raise TypeError(f"Unexpected extra arguments {args[1:]}.")
+
         return super(Function, cls).__new__(cls)
 
     @property
diff --git a/symengine/tests/test_functions.py b/symengine/tests/test_functions.py
index 3a19b122..c5241ad4 100644
--- a/symengine/tests/test_functions.py
+++ b/symengine/tests/test_functions.py
@@ -103,6 +103,15 @@ def test_derivative():
     assert i == fxy.diff(y, 1, x)
 
 
+def test_function():
+    x = Symbol("x")
+    assert Function("f")(x) == function_symbol("f", x)
+
+    raises(TypeError, lambda: Function("f", "x"))
+    raises(TypeError, lambda: Function("f", x))
+    raises(TypeError, lambda: Function())
+
+
 def test_abs():
     x = Symbol("x")
     e = abs(x)

From a165060bd2fb2d3e64770fa68ad6968689f06f38 Mon Sep 17 00:00:00 2001
From: Isuru Fernando <isuruf@gmail.com>
Date: Mon, 22 Jan 2024 21:43:00 -0600
Subject: [PATCH 2/2] add name property to FunctionSymbol

---
 symengine/lib/symengine_wrapper.in.pyx | 4 ++++
 symengine/tests/test_functions.py      | 5 ++++-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/symengine/lib/symengine_wrapper.in.pyx b/symengine/lib/symengine_wrapper.in.pyx
index 4fdc0f9c..06b85266 100644
--- a/symengine/lib/symengine_wrapper.in.pyx
+++ b/symengine/lib/symengine_wrapper.in.pyx
@@ -2841,6 +2841,10 @@ class FunctionSymbol(Function):
         name = deref(X).get_name().decode("utf-8")
         return str(name)
 
+    @property
+    def name(Basic self):
+        return self.get_name()
+
     def _sympy_(self):
         import sympy
         name = self.get_name()
diff --git a/symengine/tests/test_functions.py b/symengine/tests/test_functions.py
index c5241ad4..207add98 100644
--- a/symengine/tests/test_functions.py
+++ b/symengine/tests/test_functions.py
@@ -105,12 +105,15 @@ def test_derivative():
 
 def test_function():
     x = Symbol("x")
-    assert Function("f")(x) == function_symbol("f", x)
+    fx = Function("f")(x)
+    assert fx == function_symbol("f", x)
 
     raises(TypeError, lambda: Function("f", "x"))
     raises(TypeError, lambda: Function("f", x))
     raises(TypeError, lambda: Function())
 
+    assert fx.name == "f"
+
 
 def test_abs():
     x = Symbol("x")