BooleanField that is required and have value False always will raise ValidationError

[Lagovas]

class BooleanField(Field):

def to_python(self, value):

if isinstance(value, six.string_types) and value.lower() in ('false', '0'):

value = False

else:

value = bool(value)

return super(BooleanField, self).to_python(value)

def validate(self, value):

if not value and self.required:

raise ValidationError(self.error_messagesrequired, code='required')

In method "validate" value is "True" or "False" as python object, because called after to_python.
So if value is valid ('0' or 'false') and field is required, will be raised ValidationError.
Anyway value in "validate" will be False if value is not '0' or 'false', so method validate should be empty because always is valid.