<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _candidate_filenames():
 """Generates filenames of the form 'specktre_123AB.png'. The random noise is five characters long, which allows for 62^5 = 916 million possible filenames. """

    while True:
        random_stub = ''.join([
            random.choice(string.ascii_letters + string.digits)
            for _ in range(5)
        ])
        yield 'specktre_%s.png' % random_stub