crashed to flush np.object type carray

[rabbit8ge]

import pandas as pd, numpy as np import bcolz

df = pd.DataFrame({'a':[1,2,3]},dtype=np.object) ct = bcolz.ctable.fromdataframe(df,rootdir='e:/tmp') ct.flush() ct = bcolz.open('e:/tmp') ct.flush() # crashed in this line.