The MACAddress class is accessible via the formencode.validators module.
Examples:
>>> mac = MACAddress()
>>> mac.to_python('aa:bb:cc:dd:ee:ff')
'aabbccddeeff'
>>> mac.to_python('aa:bb:cc:dd:ee:ff:e')
Traceback (most recent call last):
...
Invalid: A MAC address must contain 12 digits and A-F; the value you gave has 13 characters
>>> mac.to_python('aa:bb:cc:dd:ee:fx')
Traceback (most recent call last):
...
Invalid: MAC addresses may only contain 0-9 and A-F (and optionally :), not 'x'
>>> MACAddress(add_colons=True).to_python('aabbccddeeff')
'aa:bb:cc:dd:ee:ff'
Messages
See the source for more information.