<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:

def gen_sites(path):
    " Seek sites by path. "

    for root, _, _ in walklevel(path, 2):
        try:
            yield Site(root)
        except AssertionError:
            continue