def copy(self):
    raise NotImplementedError('Query does not support the copy() method.')
write a pandas dataframe to an sqlite db, index on given columns
dataset/ETHPy150Open AppScale/appscale/AppServer/google/appengine/api/datastore.py/Query.copy--crossover with--dataset/ETHPy150Open CGATOxford/cgat/CGAT/Database.py/write_DataFrame