      input_formats = api_settings.DATE_INPUT_FORMATS
      datetime_parser = datetime.datetime.strptime
  
      def __init__(self, format=empty, input_formats=None, *args, **kwargs):
          self.format = format if format is not empty else self.format
          self.input_formats = input_formats if input_formats is not None else self.input_formats
          super(DateField, self).__init__(*args, **kwargs)
  
      def to_internal_value(self, value):
          if isinstance(value, datetime.datetime):
              self.fail('datetime')
 
</s> remove         self.format = format if format is not empty else self.format
        self.input_formats = input_formats if input_formats is not None else self.input_formats
 </s> add         if format is not empty:
            self.format = format
        if input_formats is not None:
            self.input_formats = input_formats </s> remove     format = api_settings.DATE_FORMAT
    input_formats = api_settings.DATE_INPUT_FORMATS
 </s> add  </s> remove     format = api_settings.TIME_FORMAT
    input_formats = api_settings.TIME_INPUT_FORMATS
 </s> add 
        if format is not empty:
            self.format = format
        if input_formats is not None:
            self.input_formats = input_formats
      input_formats = api_settings.DATE_INPUT_FORMATS
      datetime_parser = datetime.datetime.strptime
  
      def __init__(self, format=empty, input_formats=None, *args, **kwargs):
        if format is not empty:
            self.format = format
        if input_formats is not None:
            self.input_formats = input_formats
        if format is not empty:
            self.format = format
        if input_formats is not None:
            self.input_formats = input_formats
          super(DateField, self).__init__(*args, **kwargs)
  
      def to_internal_value(self, value):
          if isinstance(value, datetime.datetime):
              self.fail('datetime')
keep keep keep keep replace replace keep keep keep keep keep
 Access settings lazily, not at module import 
rest_framework/fields.py