code: def validate(self, data, all_data=None):
          '''
          None data means False, so BooleanField need to override validate()
          '''
          if data is None:
              return True, False
          else:
              return super(BooleanField, self).validate(data, all_dataf validate(self, data, all_data=None):
          '''
          None data means False, so BooleanField need to override validate()
          '''
          if data is None:
              return True, False
          else:
              return super(BooleanField, self).validate(data, all_data)
docs: None data means False, so BooleanField need to override validate()