def __init__(self, btc_addr, last_seen=None):
        if not is_btc_address(btc_addr):
            msg = "Invalid BTC Address: {0}".format(btc_addr)
            logger.warning(msg)
            raise ValueError(msg)
        self.btc_addr = btc_addr
        self.last_seen = last_seen
A farmer is a un-trusted client that provides some disk space
dataset/ETHPy150Open Storj/dataserv/dataserv/Farmer.py/Farmer.__init__