Fix error

Author: skmatti

streamz/dataframe/utils.py

@@ -2,10 +2,10 @@ def is_dataframe_like(df):
     """ Looks like a Pandas DataFrame. ** Borrowed from dask.dataframe.utils ** """
     typ = type(df)
     return (all(hasattr(typ, name)
-                for name in ('groupby', 'head', 'merge', 'mean')
+                for name in ('groupby', 'head', 'merge', 'mean'))
             and all(hasattr(df, name) for name in ('dtypes',))
             and not any(hasattr(typ, name)
-                for name in ('value_counts', 'dtype'))))
+                for name in ('value_counts', 'dtype')))
 
 
 def is_series_like(s):