code: def _extents(self):
          
          def start_and_size(idx, other_idx):
              """Return beginning and length of range based on two indexes."""
              return min(idx, other_idx), abs(idx - other_idx) + 1
  
          tc, other_tc = self._tc, self._other_tc
  
          left, width = start_and_size(tc.col_idx, other_tc.col_idx)
          top, height = start_and_size(tc.row_idx, other_tc.row_idx)
  
          return left, top, width, height
docs: A (left, top, width, height) tuple describing range extents.
  
          Note this is normalized to accommodate the various orderings of the
          corner cells provided on construction, which may be in any of four
          configurations such as (top-left, bottom-right),
          (bottom-left, top-right), etc.