<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def increment_slug(s):
 """Generate next slug for a series. Some docstore types will use slugs (see above) as document ids. To support unique ids, we'll serialize them as follows: TestUserA/my-test TestUserA/my-test-2 TestUserA/my-test-3 """

    slug_parts = s.split('-')
    # advance (or add) the serial counter on the end of this slug
    # noinspection PyBroadException
    try:
        # if it's an integer, increment it
        slug_parts[-1] = str(1 + int(slug_parts[-1]))
    except:
        # there's no counter! add one now
        slug_parts.append('2')
    return '-'.join(slug_parts)