Postcode (Dutch postal code).
The Dutch postal code consists of four numbers followed by two letters.
>>> validate('2601 DC')
'2601 DC'
>>> validate('NL-2611ET')
'2611 ET'
>>> validate('26112 ET')
Traceback (most recent call last):
...
InvalidFormat: ...
>>> validate('2611 SS') # a few letter combinations are banned
Traceback (most recent call last):
...
InvalidComponent: ...
Convert the number to the minimal representation. This strips the number of any valid separators and removes surrounding whitespace.
Checks to see if the number provided is a valid postal code.
Checks to see if the number provided is in the correct format. This currently does not check whether the code corresponds to a real address.