diff --git a/src/umlizer/inspector.py b/src/umlizer/inspector.py
index 444a9f5..ef637c3 100644
--- a/src/umlizer/inspector.py
+++ b/src/umlizer/inspector.py
@@ -288,55 +288,60 @@ def _extract_module_name(module_path: str) -> tuple[str, str]:
     return module_path, module_name
 
 
-def _get_classes_from_module(module_path: str) -> list[Type[Any]]:
+def _get_classes_from_module(module_file_path: str) -> list[Type[Any]]:
     """
-    Extract classes from a given module path using importlib.import_module.
+    Extract classes from a given module path using importlib.
 
     Parameters
     ----------
-    module_path : str
-        The path to the module from which classes are to be extracted.
+    module_file_path : str
+        The path to the module file from which classes are to be extracted.
 
     Returns
     -------
     list
         A list of class objects.
     """
-    module_path, module_name = _extract_module_name(module_path)
+    module_path, module_name = _extract_module_name(module_file_path)
     original_path = copy.deepcopy(sys.path)
 
     sys.path.insert(0, module_path)
     try:
-        module = importlib.import_module(module_name)
+        spec = importlib.util.spec_from_file_location(
+            module_name, module_file_path
+        )
+        if spec is None:
+            raise ImportError(f'Cannot find spec for {module_file_path}')
+        module = importlib.util.module_from_spec(spec)
+        sys.modules[module_name] = module
+        spec.loader.exec_module(module)  # type: ignore
+        sys.path = original_path
+
+        all_classes_exported = []
+
+        if hasattr(module, '__all__'):
+            all_classes_exported = [
+                getattr(module, name)
+                for name in module.__all__
+                if inspect.isclass(getattr(module, name))
+            ]
+
+        all_classes = [
+            getattr(module, name)
+            for name in dir(module)
+            if inspect.isclass(getattr(module, name))
+            and getattr(getattr(module, name), '__module__', None)
+            == module.__name__
+        ]
     except KeyboardInterrupt:
         raise_error('KeyboardInterrupt', 1)
     except Exception as e:
-        short_module_path = '.'.join(module_path.split('/')[-3:])
+        short_module_path = '.'.join(module_path.split(os.sep)[-3:])
         print(f' Error loading module {short_module_path} '.center(80, '='))
         print(e)
         print('.' * 80)
         sys.path = original_path
         return []
-
-    # If __all__ is defined, get only the classes listed in __all__
-    all_classes_exported = []
-    if hasattr(module, '__all__'):
-        for name in module.__all__:
-            if not inspect.isclass(getattr(module, name)):
-                continue
-            all_classes_exported.append(getattr(module, name))
-
-    # Get all classes defined directly in the module
-    all_classes = []
-    for name in dir(module):
-        if not (
-            inspect.isclass(getattr(module, name))
-            and getattr(getattr(module, name), '__module__', None)
-            == module.__name__
-        ):
-            continue
-        all_classes.append(getattr(module, name))
-    sys.path = original_path
     return all_classes + all_classes_exported
 
 
@@ -390,10 +395,12 @@ def load_classes_definition(
         module_files.append(path_str)
 
     for file_path in module_files:
+        classes_from_module = _get_classes_from_module(file_path)
+        classes_list.extend(classes_from_module)
         if verbose:
+            print('=' * 80)
             print(file_path)
-
-        classes_list.extend(_get_classes_from_module(file_path))
+            print(classes_from_module)
 
     return [_get_class_structure(cls, source) for cls in classes_list]