code: def validate(self, raw_data, **kwargs):
          
          super(BooleanField, self).validate(raw_data, **kwargs)
          if isinstance(raw_data, string_types):
              valid_data = raw_data.strip().lower() == 'true'
          elif isinstance(raw_data, bool):
              valid_data = raw_data
          else:
              valid_data = raw_data > 0
          return valid_data
docs: The string ``'True'`` (case insensitive) will be converted
          to ``True``, as will any positive integers.