def call(self): keypair = self.keypair() builder = Builder(address=keypair.address().decode(), sequence=self.random_sequence(), secret=keypair.seed()) builder.sign() builder.add_memo(self.memo()) builder.add_time_bounds(self.build_time_bounds()) builder.append_payment_op(source=Keypair.random(), destination=keypair.address().decode(), amount='0.000001') builder.sign() te = builder.gen_te() return te.xdr()