  
      def to_internal_value(self, value):
          if isinstance(value, datetime.time):
              return value
  
          for input_format in input_formats:
 
</s> remove         for format in self.input_formats:
            if format.lower() == ISO_8601:
 </s> add         for input_format in input_formats:
            if input_format.lower() == ISO_8601: </s> remove         for format in self.input_formats:
            if format.lower() == ISO_8601:
 </s> add         for input_format in input_formats:
            if input_format.lower() == ISO_8601: </s> remove         for format in self.input_formats:
            if format.lower() == ISO_8601:
 </s> add         for input_format in input_formats:
            if input_format.lower() == ISO_8601:
        input_formats = getattr(self, 'input_formats', api_settings.TIME_INPUT_FORMATS)

  
      def to_internal_value(self, value):
        input_formats = getattr(self, 'input_formats', api_settings.TIME_INPUT_FORMATS)

          if isinstance(value, datetime.time):
              return value
  
          for input_format in input_formats:
keep add keep keep keep keep
 Access settings lazily, not at module import 
rest_framework/fields.py