code: def ystep(self):
          r
  
          self.Y = sp.proj_l1(self.AX + self.U, self.gamma,
                              axis=self.cri.axisN + (self.cri.axisC,
                                                     self.cri.axisM))
          super(ConvBPDNProjL1, self).ystep()
docs: r"""Minimise Augmented Lagrangian with respect to
          :math:`\mathbf{y}`.