@@ -55,7 +55,7 @@ async def read_async(self, path: str) -> str:
     )
     @sk_function_context_parameter(name="path", description="Destination path")
     @sk_function_context_parameter(name="content", description="File content")
-    async def write_async(self, context: "SKContext"):
+    async def write_async(self, context: "SKContext") -> None:
         """
         Write a file
 
@@ -64,9 +64,6 @@ async def write_async(self, context: "SKContext"):
         Args:
             Contains the 'path' for the Destination file and
             the 'content' of the file to write.
-
-        Returns:
-            The contents of the file
         """
         has_path, path = context.variables.get("path")
         has_content, content = context.variables.get("content")
 
@@ -111,7 +111,7 @@ async def recall_async(self, ask: str, context: "SKContext") -> str:
         name=KEY_PARAM,
         description="The unique key to associate with the information",
     )
-    async def save_async(self, text: str, context: "SKContext"):
+    async def save_async(self, text: str, context: "SKContext") -> None:
         """
         Save a fact to the long term memory.
 
 
@@ -18,7 +18,7 @@ class WaitSkill(PydanticField):
     """
 
     @sk_function(description="Wait for a certain number of seconds.")
-    async def wait(self, seconds_text: str):
+    async def wait(self, seconds_text: str) -> None:
         try:
             seconds = max(float(seconds_text), 0)
         except ValueError:
 
@@ -734,26 +734,22 @@ def import_native_skill_from_directory(
             )
 
         skill_name = os.path.basename(skill_directory)
-        try:
-            spec = importlib.util.spec_from_file_location(
-                MODULE_NAME, native_py_file_path
-            )
-            module = importlib.util.module_from_spec(spec)
-            spec.loader.exec_module(module)
 
-            class_name = next(
-                (
-                    name
-                    for name, cls in inspect.getmembers(module, inspect.isclass)
-                    if cls.__module__ == MODULE_NAME
-                ),
-                None,
-            )
-            if class_name:
-                skill_obj = getattr(module, class_name)()
-                return self.import_skill(skill_obj, skill_name)
-        except Exception:
-            pass
+        spec = importlib.util.spec_from_file_location(MODULE_NAME, native_py_file_path)
+        module = importlib.util.module_from_spec(spec)
+        spec.loader.exec_module(module)
+
+        class_name = next(
+            (
+                name
+                for name, cls in inspect.getmembers(module, inspect.isclass)
+                if cls.__module__ == MODULE_NAME
+            ),
+            None,
+        )
+        if class_name:
+            skill_obj = getattr(module, class_name)()
+            return self.import_skill(skill_obj, skill_name)
 
         return {}
 
 
@@ -39,6 +39,10 @@ def _return_is_context(signature: Signature) -> bool:
     return _is_annotation_of_type(signature.return_annotation, SKContext)
 
 
+def _return_is_none(signature: Signature) -> bool:
+    return signature.return_annotation is None
+
+
 def _no_return(signature: Signature) -> bool:
     return signature.return_annotation is Signature.empty
 
@@ -79,7 +83,7 @@ class DelegateInference(PydanticField):
     @_infers(DelegateTypes.Void)
     def infer_void(signature: Signature, awaitable: bool) -> bool:
         matches = _has_no_params(signature)
-        matches = matches and _no_return(signature)
+        matches = matches and _return_is_none(signature)
         matches = matches and not awaitable
         return matches
 
@@ -103,7 +107,7 @@ def infer_out_task_string(signature: Signature, awaitable: bool) -> bool:
     @_infers(DelegateTypes.InSKContext)
     def infer_in_sk_context(signature: Signature, awaitable: bool) -> bool:
         matches = _first_param_is_context(signature)
-        matches = matches and _no_return(signature)
+        matches = matches and _return_is_none(signature)
         matches = matches and not awaitable
         return matches
 
@@ -139,7 +143,7 @@ def infer_context_switch_in_sk_context_out_task_sk_context(
     @_infers(DelegateTypes.InString)
     def infer_in_string(signature: Signature, awaitable: bool) -> bool:
         matches = _first_param_is_str(signature)
-        matches = matches and _no_return(signature)
+        matches = matches and _return_is_none(signature)
         matches = matches and not awaitable
         return matches
 
@@ -164,7 +168,7 @@ def infer_in_string_out_task_string(signature: Signature, awaitable: bool) -> bo
     def infer_in_string_and_context(signature: Signature, awaitable: bool) -> bool:
         matches = _first_param_is_str(signature, only=False)
         matches = matches and _has_two_params_second_is_context(signature)
-        matches = matches and _no_return(signature)
+        matches = matches and _return_is_none(signature)
         matches = matches and not awaitable
         return matches
 
@@ -205,15 +209,15 @@ def infer_context_switch_in_string_and_context_out_task_context(
     @_infers(DelegateTypes.InStringOutTask)
     def infer_in_string_out_task(signature: Signature, awaitable: bool) -> bool:
         matches = _first_param_is_str(signature)
-        matches = matches and _no_return(signature)
+        matches = matches and _return_is_none(signature)
         matches = matches and awaitable
         return matches
 
     @staticmethod
     @_infers(DelegateTypes.InContextOutTask)
     def infer_in_context_out_task(signature: Signature, awaitable: bool) -> bool:
         matches = _first_param_is_context(signature)
-        matches = matches and _no_return(signature)
+        matches = matches and _return_is_none(signature)
         matches = matches and awaitable
         return matches
 
@@ -224,15 +228,14 @@ def infer_in_string_and_context_out_task(
     ) -> bool:
         matches = _first_param_is_str(signature, only=False)
         matches = matches and _has_two_params_second_is_context(signature)
-        matches = matches and _no_return(signature)
+        matches = matches and _return_is_none(signature)
         matches = matches and awaitable
         return matches
 
     @staticmethod
     @_infers(DelegateTypes.OutTask)
     def infer_out_task(signature: Signature, awaitable: bool) -> bool:
         matches = _has_no_params(signature)
-        matches = matches and _no_return(signature)
         matches = matches and awaitable
         return matches
 
@@ -249,6 +252,13 @@ def infer_unknown(signature: Signature, awaitable: bool) -> NoReturn:
     def infer_delegate_type(function) -> DelegateTypes:
         # Get the function signature
         function_signature = signature(function)
+
+        if _no_return(function_signature):
+            raise KernelException(
+                KernelException.ErrorCodes.FunctionTypeNotSupported,
+                "No return type specified, unable to infer DelegateType.",
+            )
+
         awaitable = iscoroutinefunction(function)
 
         for name, value in DelegateInference.__dict__.items():
 
@@ -132,7 +132,7 @@ def create_plan(self, goal: str) -> Plan:
     @sk_function_context_parameter(
         name="function_descriptions", description="List of tool descriptions"
     )
-    async def execute_plan_async(self, context: SKContext):
+    async def execute_plan_async(self, context: SKContext) -> SKContext:
         question = context["question"]
 
         steps_taken: List[SystemStep] = []
 
@@ -1,25 +1,32 @@
 # Copyright (c) Microsoft. All rights reserved.
 
+from typing import TYPE_CHECKING
+
 from semantic_kernel.orchestration.sk_function import SKFunction
 from semantic_kernel.skill_definition.sk_function_decorator import sk_function
 
+if TYPE_CHECKING:
+    from semantic_kernel.orchestration.sk_context import SKContext
+
 
 def test_init_native_function_with_input_description():
-    class MockMethodWithInputDescription:
-        __sk_function__ = True
-        __sk_function_name__ = "mock_function"
-        __sk_function_description__ = "Mock description"
-        __sk_function_input_description__ = "Mock input description"
-        __sk_function_input_default_value__ = "default_input_value"
-        __sk_function_context_parameters__ = [
-            {
-                "name": "param1",
-                "description": "Param 1 description",
-                "default_value": "default_param1_value",
-            }
-        ]
-
-    mock_method = MockMethodWithInputDescription
+    def mock_function(input: str, context: "SKContext") -> None:
+        pass
+
+    mock_function.__sk_function__ = True
+    mock_function.__sk_function_name__ = "mock_function"
+    mock_function.__sk_function_description__ = "Mock description"
+    mock_function.__sk_function_input_description__ = "Mock input description"
+    mock_function.__sk_function_input_default_value__ = "default_input_value"
+    mock_function.__sk_function_context_parameters__ = [
+        {
+            "name": "param1",
+            "description": "Param 1 description",
+            "default_value": "default_param1_value",
+        }
+    ]
+
+    mock_method = mock_function
 
     native_function = SKFunction.from_native_method(mock_method, "MockSkill")
 
@@ -33,19 +40,21 @@ class MockMethodWithInputDescription:
 
 
 def test_init_native_function_without_input_description():
-    class MockMethodWithoutInputDescription:
-        __sk_function__ = True
-        __sk_function_name__ = "mock_function_no_input_desc"
-        __sk_function_description__ = "Mock description no input desc"
-        __sk_function_context_parameters__ = [
-            {
-                "name": "param1",
-                "description": "Param 1 description",
-                "default_value": "default_param1_value",
-            }
-        ]
-
-    mock_method = MockMethodWithoutInputDescription
+    def mock_function(context: "SKContext") -> None:
+        pass
+
+    mock_function.__sk_function__ = True
+    mock_function.__sk_function_name__ = "mock_function_no_input_desc"
+    mock_function.__sk_function_description__ = "Mock description no input desc"
+    mock_function.__sk_function_context_parameters__ = [
+        {
+            "name": "param1",
+            "description": "Param 1 description",
+            "default_value": "default_param1_value",
+        }
+    ]
+
+    mock_method = mock_function
 
     native_function = SKFunction.from_native_method(mock_method, "MockSkill")
 
@@ -62,7 +71,7 @@ def test_init_native_function_from_sk_function_decorator():
         input_description="Test input description",
         input_default_value="test_default_value",
     )
-    def decorated_function():
+    def decorated_function() -> None:
         pass
 
     assert decorated_function.__sk_function__ is True
@@ -85,7 +94,7 @@ def decorated_function():
 
 def test_init_native_function_from_sk_function_decorator_defaults():
     @sk_function()
-    def decorated_function():
+    def decorated_function() -> None:
         pass
 
     assert decorated_function.__sk_function__ is True
Original file line number	Diff line number	Diff line change
`@@ -111,7 +111,7 @@ async def recall_async(self, ask: str, context: "SKContext") -> str:`
`111`	`111`	`name=KEY_PARAM,`
`112`	`112`	`description="The unique key to associate with the information",`
`113`	`113`	`)`
`114`		`- async def save_async(self, text: str, context: "SKContext"):`
	`114`	`+ async def save_async(self, text: str, context: "SKContext") -> None:`
`115`	`115`	`"""`
`116`	`116`	`Save a fact to the long term memory.`
`117`	`117`
Original file line number	Diff line number	Diff line change
`@@ -132,7 +132,7 @@ def create_plan(self, goal: str) -> Plan:`
`132`	`132`	`@sk_function_context_parameter(`
`133`	`133`	`name="function_descriptions", description="List of tool descriptions"`
`134`	`134`	`)`
`135`		`- async def execute_plan_async(self, context: SKContext):`
	`135`	`+ async def execute_plan_async(self, context: SKContext) -> SKContext:`
`136`	`136`	`question = context["question"]`
`137`	`137`
`138`	`138`	`steps_taken: List[SystemStep] = []`