def clean(self, value):
        v = super(CZPostalCodeField, self).clean(value)
        return v.replace(' ', '')
Validates the input and returns a string that contains only numbers.
dataset/ETHPy150Open AppScale/appscale/AppServer/lib/django-1.5/django/contrib/localflavor/cz/forms.py/CZPostalCodeField.clean