Traceback (most recent call last):


 "<stdin>", line 1, in <module>


 "/home/ec2-user/.local/lib/python3.6/site-packages/dask/dataframe/core.py", line 1648, in count

result.divisions = (min(self.columns), max(self.columns))
ValueError: min() arg is an empty sequence

Traceback (most recent call last):


 "/usr/lib/python2.7/dist-packages/pyface/workbench/workbench.py", line 319, in _restore_window_layout

memento = six.moves.cPickle.load(f)
ValueError: unsupported pickle protocol: 3
