docs: def bbox(self, outname=None, format='ESRI Shapefile', overwrite=True):
          """
          create a bounding box from the extent of the Vector object
  
          Parameters
          ----------
          outname: str or None
              the name of the vector file to be written; if None, a Vector object is returned
          format: str
              the name of the file format to write
          overwrite: bool
              overwrite an already existing file?
  
          Returns
          -------
          Vector or None
              if outname is None, the bounding box Vector object
          """
          if outname is None:
              return bbox(self.extent, self.srs)
          else:
              bbox(self.extent, self.srs, outname=outname, format=format, overwrite=overwrite)