code: def clip_extents(self):
          
          extents = ffi.new('double[4]')
          cairo.cairo_clip_extents(
              self._pointer, extents + 0, extents + 1, extents + 2, extents + 3)
          self._check_status()
          return tuple(extents)
docs: Computes a bounding box in user coordinates
          covering the area inside the current clip.
  
          :return:
              A ``(x1, y1, x2, y2)`` tuple of floats:
              the left, top, right and bottom of the resulting extents,
              respectively.