pandas write to disk
df.to_csv(path_or_buf=None, sep=',', na_rep='', float_format=None,
columns=None, header=True, index=True, index_label=None,
mode='w', encoding=None, compression='infer',
quoting=None, quotechar='"', line_terminator=None,
chunksize=None, date_format=None, doublequote=True,
escapechar=None, decimal='.', errors='strict')