import random


def null_boolean_field_data(field, **kwargs):
    """
    Return random value for NullBooleanField
    
    >>> result = any_form_field(forms.NullBooleanField())
    >>> type(result)
    <type 'unicode'>
    >>> result in [u'1', u'2', u'3']
    True
    """
    return random.choice(['None', 'True', 'False'])