diff --git a/python-ecosys/requests/requests/__init__.py b/python-ecosys/requests/requests/__init__.py
index a9a183619..663a4f608 100644
--- a/python-ecosys/requests/requests/__init__.py
+++ b/python-ecosys/requests/requests/__init__.py
@@ -46,6 +46,8 @@ def request(
 ):
     if headers is None:
         headers = {}
+    else:
+        headers = headers.copy()    # local copy so we don't extend caller's
 
     redirect = None  # redirection url, None means no redirection
     chunked_data = data and getattr(data, "__next__", None) and not getattr(data, "__len__", None)