def increment_legacy_tag(self):
self._legacy_tag = (<EOL>Tag.from_trits(add_trits(self.legacy_tag.as_trits(), [<NUM_LIT:1>]))<EOL>)<EOL>
Increments the transaction's legacy tag, used to fix insecure
bundle hashes when finalizing a bundle.

References:

- https://github.com/iotaledger/iota.lib.py/issues/84