def byChain(df, gen=gen16.ts[0], hi=16, lo=15):
    return df.assign(chain=np.where((df.blockTime >= gen), hi, lo))
    return df
def byChain(df, gen=gen16.ts[0], hi=16, lo=15):
    return df.assign(chain=np.where((df.blockTime >= gen), hi, lo))
    return df