code: def wnextd(side, window):
      
      assert isinstance(window, stypes.SpiceCell)
      assert window.dtype == 1
      assert side == 'L' or side == 'R'
      side = ctypes.c_char(side.encode(encoding='UTF-8'))
      libspice.wnextd_c(side, ctypes.byref(window))
      return window
docs: Extract the left or right endpoints from a double precision
      window.
  
      http://naif.jpl.nasa.gov/pub/naif/toolkit_docs/C/cspice/wnextd_c.html
  
      :param side: Extract left "L" or right "R" endpoints. 
      :type side: str
      :param window: Window to be extracted. 
      :type window: spiceypy.utils.support_types.SpiceCell
      :return: Extracted Window.
      :rtype: spiceypy.utils.support_types.SpiceCell