default to None

Author: ResidentMario

pandas/core/internals.py

@@ -358,7 +358,7 @@ def apply(self, func, mgr=None, **kwargs):
         return result
 
     def fillna(self, value, limit=None, inplace=False, downcast=None,
-               errors='coerce', mgr=None):
+               errors=None, mgr=None):
         """ fillna on the block with the value. If we fail, then convert to
         ObjectBlock and try again
         """