Ensure _get_function_full_qual_name() can get always get the module name (#62)

* Ensure _get_function_full_qual_name() can get the module name when the module is imported through importlib

* lint

Co-authored-by: Stanley Hsieh <pehsieh@microsoft.com>

Author: ysmu

inference_schema/schema_util.py

@@ -3,7 +3,6 @@
 # ---------------------------------------------------------
 
 import copy
-import inspect
 
 from inference_schema._constants import INPUT_SCHEMA_ATTR, OUTPUT_SCHEMA_ATTR
 
@@ -108,10 +107,9 @@ def _get_function_full_qual_name(func):
     :rtype: str
     """
 
-    decorators = _get_decorators(func)
-    base_func_name = decorators[-1].__name__
-    module = inspect.getmodule(decorators[-1])
-    module_name = "" if module is None else module.__name__
+    original_func = _get_decorators(func)[-1]
+    base_func_name = original_func.__name__
+    module_name = getattr(original_func, '__module__', '<unknown>')
     return '{}.{}'.format(module_name, base_func_name)