code: def add(A, b, offset=0):
      
      return _diag_ufunc(A, b, offset, np.add)
docs: Add b to the view of A in place (!).
      Returns modified A.
      Broadcasting is allowed, thus b can be scalar.
  
      if offset is not zero, make sure b is of right shape!
  
      :param ndarray A: 2 dimensional array
      :param ndarray-like b: either one dimensional or scalar
      :param int offset: same as in view.
      :rtype: view of A, which is adjusted inplace