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()
