diff --git a/moto/moto_proxy/utils.py b/moto/moto_proxy/utils.py
index afb94f094..76f68be81 100644
--- a/moto/moto_proxy/utils.py
+++ b/moto/moto_proxy/utils.py
@@ -13,10 +13,10 @@ def get_body_from_form_data(
         return
 
     def on_part_data(b,s,e):
-        print("YO PART DATA", b, s, e)
+        print("YO PART DATA", b[s:e])
         return
 
-    def on_part_end(string: str):
+    def on_part_end():
         print("YO PART ENDED")
         return
 
@@ -29,11 +29,11 @@ def get_body_from_form_data(
         return
 
     def on_header_field(b,s,e):
-        print("YO HEADER FIELD", b, s, e)
+        print("YO HEADER FIELD", b[s:e])
         return
 
     def on_header_value(b,s,e):
-        print("YO HEADER FIELD", b, s, e)
+        print("YO HEADER VALUE", b[s:e])
         return
 
     def on_headers_finished():