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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def validate_auth_mechanism(option, value):
 """Validate the authMechanism URI option. """

    # CRAM-MD5 is for server testing only. Undocumented,
    # unsupported, may be removed at any time. You have
    # been warned.
    if value not in MECHANISMS and value != 'CRAM-MD5':
        raise ValueError("%s must be in %s" % (option, tuple(MECHANISMS)))
    return value