[python-experimental] Raise builtin AttributeError instead of custom ApiKeyError (#6229)

* Use AttributeError instead of ApiKeyError because that's what the hasattr builtin function uses

* Use AttributeError instead of ApiKeyError because that's what the hasattr builtin function uses

* fix unit tests

* create ApiAttributeError exception

* fix formatting

* run samples scripts

samples/client/petstore/python-asyncio/petstore_api/__init__.py

@@ -31,6 +31,7 @@ from petstore_api.exceptions import OpenApiException
 from petstore_api.exceptions import ApiTypeError
 from petstore_api.exceptions import ApiValueError
 from petstore_api.exceptions import ApiKeyError
+from petstore_api.exceptions import ApiAttributeError
 from petstore_api.exceptions import ApiException
 # import models into sdk package
 from petstore_api.models.additional_properties_any_type import AdditionalPropertiesAnyType

samples/client/petstore/python-asyncio/petstore_api/exceptions.py

@@ -64,6 +64,25 @@ class ApiValueError(OpenApiException, ValueError):
         super(ApiValueError, self).__init__(full_msg)
 
 
+class ApiAttributeError(OpenApiException, AttributeError):
+    def __init__(self, msg, path_to_item=None):
+        """
+        Raised when an attribute reference or assignment fails.
+
+        Args:
+            msg (str): the exception message
+
+        Keyword Args:
+            path_to_item (None/list) the path to the exception in the
+                received_data dict
+        """
+        self.path_to_item = path_to_item
+        full_msg = msg
+        if path_to_item:
+            full_msg = "{0} at {1}".format(msg, render_path(path_to_item))
+        super(ApiAttributeError, self).__init__(full_msg)
+
+
 class ApiKeyError(OpenApiException, KeyError):
     def __init__(self, msg, path_to_item=None):
         """