def METHOD_NAME(V):
    class MyExpression:
        def __init__(self):
            self.t = 0.0
        def eval(self, x):
            return np.full(x.shape[1], self.t)
    f = MyExpression()
    f.t = 1.0
    w = Function(V)
    w.interpolate(f.eval)
    assert (w.x.array[:] == 1.0).all()
    num_vertices = V.mesh.topology.index_map(0).size_global
    assert np.isclose(w.x.norm(la.Norm.l1) - num_vertices, 0)
    f.t = 2.0
    w.interpolate(f.eval)
    assert (w.x.array[:] == 2.0).all()