def bp_to_rshares(self, steem_power, post_rshares=0, voting_power=STEEM_100_PERCENT, vote_pct=STEEM_100_PERCENT, use_stored_data=True):
        """ Obtain the r-shares from Steem power

            :param number steem_power: Steem Power
            :param int post_rshares: rshares of post which is voted