def get_next_base26(prev=None):
if not prev:<EOL><INDENT>return '<STR_LIT:a>'<EOL><DEDENT>r = re.compile("<STR_LIT>")<EOL>if not r.match(prev):<EOL><INDENT>raise ValueError("<STR_LIT>")<EOL><DEDENT>if not prev.endswith('<STR_LIT:z>'):<EOL><INDENT>return prev[:-<NUM_LIT:1>] + chr(ord(prev[-<NUM_LIT:1>]) + <NUM_LIT:1>)<EOL><DEDENT>return get_next_base26(prev[:-<NUM_LIT:1>]) + '<STR_LIT:a>'<EOL>
Increment letter-based IDs.

    Generates IDs like ['a', 'b', ..., 'z', 'aa', ab', ..., 'az', 'ba', ...]

    Returns:
        str: Next base-26 ID.