code: def adjoint(self):
          
  
          if not self.is_linear:
              raise OpNotImplementedError('nonlinear operators have no adjoint')
  
          return OperatorComp(self.functional.adjoint, self.vector.T)
docs: Adjoint of this operator.
  
              ``FunctionalLeftVectorMult(op, y).adjoint ==
              OperatorComp(op.adjoint, y.T)``
  
          Returns
          -------
          adjoint : `OperatorComp`
  
          Raises
          ------
          OpNotImplementedError
              If the underlying operator is non-linear.