docs: def perm_j(j1, j2):
      r"""Calculate the allowed total angular momenta.
  
      >>> from sympy import Integer
      >>> L = 1
      >>> S = 1/Integer(2)
      >>> perm_j(L, S)
      [1/2, 3/2]
  
      """
      jmin = abs(j1-j2)
      jmax = j1+j2
      return [jmin + i for i in range(jmax-jmin+1)]