docs: def mdgel_metadata(self):
          """Return consolidated metadata from MD GEL tags as dict."""
          for page in self.pages[:2]:
              if 'MDFileTag' in page.tags:
                  tags = page.tags
                  break
          else:
              return None
          result = {}
          for code in range(33445, 33453):
              name = TIFF.TAGS[code]
              if name not in tags:
                  continue
              result[name[2:]] = tags[name].value
          return result