Don't disable existing logger when initializing qlib. (#1339)

* Don't disable existing logger when initializing qlib.

* Add comma in the end of the config line.

* Add comment to the added config.

Co-authored-by: Jinge Wang <jingewang@microsoft.com>

qlib/config.py

@@ -172,6 +172,9 @@ def register_from_C(self, config, skip_register=True):
             }
         },
         "loggers": {"qlib": {"level": logging.DEBUG, "handlers": ["console"]}},
+        # To let qlib work with other packages, we shouldn't disable existing loggers.
+        # Note that this param is default to True according to the documentation of logging.
+        "disable_existing_loggers": False,
     },
     # Default config for experiment manager
     "exp_manager": {