def add_trits(left, right):<EOL>
target_len = max(len(left), len(right))<EOL>res = [<NUM_LIT:0>] * target_len<EOL>left += [<NUM_LIT:0>] * (target_len - len(left))<EOL>right += [<NUM_LIT:0>] * (target_len - len(right))<EOL>carry = <NUM_LIT:0><EOL>for i in range(len(res)):<EOL><INDENT>res[i], carry = _full_add_trits(left[i], right[i], carry)<EOL><DEDENT>return res<EOL>
Adds two sequences of trits together.

The result is a list of trits equal in length to the longer of the
two sequences.

.. note::
    Overflow is possible.

    For example, ``add_trits([1], [1])`` returns ``[-1]``.