code: def focus_down(pymux):
      " Move focus down. "
      _move_focus(pymux,
                  lambda wp: wp.xpos,
                  lambda wp: wp.ypos + wp.height + 2f focus_down(pymux):
      " Move focus down. "
      _move_focus(pymux,
                  lambda wp: wp.xpos,
                  lambda wp: wp.ypos + wp.height + 2)
docs: Move focus down.