def creates(self):
        "returns the address of a contract created by this tx"
        if self.to in (b'', '\0' * 20):
            return mk_contract_address(self.sender, self.nonce)
def creates ( self ) : if self . to in ( b'' , '\0' * 20 ) : return mk_contract_address ( self . sender , self . nonce )
returns the address of a contract created by this tx