diff --git a/litellm/llms/vertex_ai/common_utils.py b/litellm/llms/vertex_ai/common_utils.py
index c731ced1263..560810f3486 100644
--- a/litellm/llms/vertex_ai/common_utils.py
+++ b/litellm/llms/vertex_ai/common_utils.py
@@ -820,7 +820,7 @@ def convert_anyof_null_to_nullable(schema, depth=0):
     anyof: Final = schema.get("anyOf", None)
     if anyof is not None:
         contains_null = False
-        for atype in list(anyof):
+        for atype in tuple(anyof):
             if isinstance(atype, dict) and atype.get("type") == "null":
                 # remove null type
                 anyof.remove(atype)
diff --git a/tests/code_coverage_tests/recursive_detector.py b/tests/code_coverage_tests/recursive_detector.py
index 244e17b46a1..9c871b54802 100644
--- a/tests/code_coverage_tests/recursive_detector.py
+++ b/tests/code_coverage_tests/recursive_detector.py
@@ -11,6 +11,7 @@ IGNORE_FUNCTIONS = [
     "clean_message",
     "unpack_defs",
     "convert_anyof_null_to_nullable",  # has a set max depth
+    "_convert_oneof_to_anyof",  # has a set max depth
     "add_object_type",
     "strip_field",
     "_transform_prompt",