code: def wnfetd(window, n):
      
      assert isinstance(window, stypes.SpiceCell)
      assert window.dtype == 1
      n = ctypes.c_int(n)
      left = ctypes.c_double()
      right = ctypes.c_double()
      libspice.wnfetd_c(ctypes.byref(window), n, ctypes.byref(left),
                        ctypes.byref(right))
      return left.value, right.value
docs: Fetch a particular interval from a double precision window.
  
      http://naif.jpl.nasa.gov/pub/naif/toolkit_docs/C/cspice/wnfetd_c.html
  
      :param window: Input window 
      :type window: spiceypy.utils.support_types.SpiceCell
      :param n: Index of interval to be fetched. 
      :type n: int
      :return: Left, right endpoints of the nth interval.
      :rtype: tuple