  def get_readable_date_format(date_format):
      mapping = [("%Y", "YYYY"),
                 ("%y", "YY"),
                 ("%m", "MM"),
                 ("%b", "[Jan through Dec]"),
                 ("%B", "[January through December]"),
                 ("%d", "DD"),
                 ("%H", "HH"),
                 ("%M", "MM"),
                 ("%S", "SS"),
                 ("%f", "uuuuuu")]
      for k, v in mapping:
          date_format = date_format.replace(k, v)
      return date_format 
</s> remove             if format.lower() == ISO8601:
 </s> add             if format.lower() == ISO_8601: </s> remove             if format.lower() == ISO8601:
 </s> add             if format.lower() == ISO_8601: </s> remove             if format.lower() == ISO8601:
 </s> add             if format.lower() == ISO_8601: </s> remove         self.output_format = output_format if output_format is not None else self.output_format
 </s> add         self.format = format if format is not None else self.format </s> remove         self.output_format = output_format if output_format is not None else self.output_format
 </s> add         self.format = format if format is not None else self.format
replace replace replace replace replace replace replace replace replace replace replace replace replace replace
 Clean ups to datetime formatting 
rest_framework/utils/dates.py