diff --git a/k8sclient/client/api_client.py b/k8sclient/client/api_client.py
index 9d075c0..62bd226 100644
--- a/k8sclient/client/api_client.py
+++ b/k8sclient/client/api_client.py
@@ -187,7 +187,7 @@ class ApiClient(object):
         """
         if isinstance(obj, type(None)):
             return None
-        elif isinstance(obj, (str, int, float, bool, tuple)):
+        elif isinstance(obj, (unicode, str, int, float, bool, tuple, file)):
             return obj
         elif isinstance(obj, list):
             return [self.sanitize_for_serialization(sub_obj)