code: def get_bounds(changeset):
      
      try:
          return Polygon([
              (float(changeset.get('min_lon')), float(changeset.get('min_lat'))),
              (float(changeset.get('max_lon')), float(changeset.get('min_lat'))),
              (float(changeset.get('max_lon')), float(changeset.get('max_lat'))),
              (float(changeset.get('min_lon')), float(changeset.get('max_lat'))),
              (float(changeset.get('min_lon')), float(changeset.get('min_lat'))),
              ])
      except TypeError:
          return Polygon()
docs: Get the bounds of the changeset and return it as a Polygon object. If
      the changeset has not coordinates (case of the changesets that deal only
      with relations), it returns an empty Polygon.
  
      Args:
          changeset: the XML string of the changeset.