diff --git a/moto/moto_proxy/utils.py b/moto/moto_proxy/utils.py
index e1ea42dec..afb94f094 100644
--- a/moto/moto_proxy/utils.py
+++ b/moto/moto_proxy/utils.py
@@ -8,7 +8,7 @@ def get_body_from_form_data(
 ) -> Tuple[Optional[bytes], Dict[str, str]]:
     print("YO BYTES", body)
 
-    def on_part_begin(string: str):
+    def on_part_begin():
         print("YO PART BEGAN")
         return
 
@@ -54,7 +54,7 @@ def get_body_from_form_data(
                                            "on_header_end": on_header_end,
                                            "on_headers_finished": on_headers_finished,
                                            "on_end": on_end,
-                                       },
+                                       }
                                        )
     parser.write(body)
     parser.finalize(body)