How to use the tinytag.tinytag.ID3.FID_TO_FIELD.get function in tinytag

def _parse_frame(self, fh, is_v22=False):
        encoding = 'ISO-8859-1'  # default encoding used in most mp3 tags
        # ID3v2.2 especially ugly. see: http://id3.org/id3v2-00
        frame_header_size = 6 if is_v22 else 10
        frame_size_bytes = 3 if is_v22 else 4
        binformat = '3s3B' if is_v22 else '4s4B2B'
        frame_header_data = fh.read(frame_header_size)
        if len(frame_header_data) == 0:
            return 0
        frame = struct.unpack(binformat, frame_header_data)
        frame_id = self._decode_string(frame[0])
        frame_size = self._calc_size_7bit_bytes(frame[1:1+frame_size_bytes])
        if frame_size > 0:
            # flags = frame[1+frame_size_bytes:] # dont care about flags.
            content = fh.read(frame_size)
            fieldname = ID3.FID_TO_FIELD.get(frame_id)
            if fieldname:
                if fieldname == 'track':
                    self._parse_track(content)
                else:
                    self._set_field(fieldname, content, self._decode_string)
            return frame_size
        return 0