field_values.py

# Returns the different values of a field in a django model.
# Because I didn't want to check the docs and needed a way that didn't retrieve lots of records from the database.
# It was fun to code and uses a couple of Python tricks.
def field_values(cls, field):
    values = []
    exclude_args = {field + '__in': values}
    while True:
        try:
            obj = cls.objects.exclude(**exclude_args)[0]
            values.append(getattr(obj, field))
        except IndexError: 
            return values