<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def serialize_b58(self, private=True):
 """Encode the serialized node in base58."""

        return ensure_str(
            base58.b58encode_check(unhexlify(self.serialize(private))))