code: def cnst_A(self, X, Xf=None):
          r
  
          return np.concatenate((self.cnst_A0(X, Xf),
                                 self.cnst_A1(X)), axis=-1)
docs: r"""Compute :math:`A \mathbf{x}` component of ADMM problem
          constraint.  In this case :math:`A \mathbf{x} = (\Gamma_0^T \;\;
          \Gamma_1^T \;\; \ldots \;\; I)^T \mathbf{x}`.