bug fix

transport/sql.py

@@ -303,7 +303,8 @@ class BQWriter(BigQuery,Writer):
                 self.mode['destination_table'] = _args['table'].strip()
             if 'schema' in _args :
                 self.mode['table_schema'] = _args['schema']
-            _mode = copy.deepcopy(self.mode)
+            # _mode = copy.deepcopy(self.mode)
+            _mode = self.mode
             _df.to_gbq(**self.mode) #if_exists='append',destination_table=partial,credentials=credentials,chunksize=90000)	
             
         pass