def METHOD_NAME(self, operators, coefficients, identity_shift=0., solver_options=None, name=None):
    if not all(isinstance(op, NGSolveMatrixOperator) for op in operators):
        return None
    if identity_shift != 0:
        return None
    matrix = operators[0].matrix.CreateMatrix()
    matrix.AsVector().data = float(coefficients[0]) * matrix.AsVector()
    for op, c in zip(operators[1:], coefficients[1:]):
        matrix.AsVector().data += float(c) * op.matrix.AsVector()
    return NGSolveMatrixOperator(matrix, self.range, self.source, solver_options=solver_options, name=name)