diff --git a/src/diffusers/pipelines/pipeline_utils.py b/src/diffusers/pipelines/pipeline_utils.py
index 2d1bb98904..b550de03b0 100644
--- a/src/diffusers/pipelines/pipeline_utils.py
+++ b/src/diffusers/pipelines/pipeline_utils.py
@@ -19,9 +19,10 @@ import inspect
 import os
 import re
 import sys
+import types
 from dataclasses import dataclass
 from pathlib import Path
-from typing import Any, Callable, Dict, Optional, Union, get_args, get_origin
+from typing import Any, Callable, Optional, Union, get_args, get_origin
 
 import httpx
 import numpy as np
@@ -1073,6 +1074,7 @@ class DiffusionPipeline(ConfigMixin, PushToHubMixin):
             )
 
         # 10. Type checking init arguments
+        print(f"{expected_types.keys()=}")
         for kw, arg in init_kwargs.items():
             # Too complex to validate with type annotation alone
             if "scheduler" in kw:
@@ -1816,9 +1818,9 @@ class DiffusionPipeline(ConfigMixin, PushToHubMixin):
         for k, v in inspect.signature(cls.__init__).parameters.items():
             if inspect.isclass(v.annotation):
                 signature_types[k] = (v.annotation,)
-            elif get_origin(v.annotation) == Union:
+            elif get_origin(v.annotation) in [Union, types.UnionType]:
                 signature_types[k] = get_args(v.annotation)
-            elif get_origin(v.annotation) in [list, Dict, list, dict]:
+            elif get_origin(v.annotation) in [list, dict]:
                 signature_types[k] = (v.annotation,)
             else:
                 logger.warning(f"cannot get type annotation for Parameter {k} of {cls}.")
diff --git a/src/diffusers/utils/source_code_parsing_utils.py b/src/diffusers/utils/source_code_parsing_utils.py
index c69b40d11b..5f94711c21 100644
--- a/src/diffusers/utils/source_code_parsing_utils.py
+++ b/src/diffusers/utils/source_code_parsing_utils.py
@@ -12,7 +12,7 @@ class ReturnNameVisitor(ast.NodeVisitor):
 
     def visit_Return(self, node):
         # Check if the return value is a tuple.
-        if isinstance(node.value, ast.tuple):
+        if isinstance(node.value, ast.Tuple):
             for elt in node.value.elts:
                 if isinstance(elt, ast.Name):
                     self.return_names.append(elt.id)