def METHOD_NAME():
    """Test MobileNetV2.
    Modified from mmclassification.
    """
    from torch.nn.modules import GroupNorm
    from mmaction.models.backbones.mobilenet_v2 import InvertedResidual
    def is_norm(modules):
        """Check if is one of the norms."""
        if isinstance(modules, (GroupNorm, _BatchNorm)):
            return True
        return False
    def is_block(modules):
        """Check if is ResNet building block."""
        if isinstance(modules, (InvertedResidual, )):
            return True
        return False
    with pytest.raises(TypeError):
        # pretrained must be a string path
        model = MobileNetV2()
        model.init_weights(pretrained=0)
    with pytest.raises(ValueError):
        # frozen_stages must in range(1, 9)
        MobileNetV2(frozen_stages=9)
    with pytest.raises(ValueError):
        # tout_indices in range(-1, 8)
        MobileNetV2(out_indices=[8])
    input_shape = (1, 3, 224, 224)
    imgs = generate_backbone_demo_inputs(input_shape)
    # Test MobileNetV2 with first stage frozen
    frozen_stages = 1
    model = MobileNetV2(frozen_stages=frozen_stages)
    model.init_weights()
    model.train()
    for mod in model.conv1.modules():
        for param in mod.parameters():
            assert param.requires_grad is False
    for i in range(1, frozen_stages + 1):
        layer = getattr(model, f'layer{i}')
        for mod in layer.modules():
            if isinstance(mod, _BatchNorm):
                assert mod.training is False
        for param in layer.parameters():
            assert param.requires_grad is False
    # Test MobileNetV2 with all stages frozen
    frozen_stages = 8
    model = MobileNetV2(frozen_stages=frozen_stages)
    model.init_weights()
    model.train()
    for mod in model.modules():
        if not isinstance(mod, MobileNetV2):
            assert mod.training is False
        for param in mod.parameters():
            assert param.requires_grad is False
    # Test MobileNetV2 with norm_eval=True
    model = MobileNetV2(norm_eval=True)
    model.init_weights()
    model.train()
    assert check_norm_state(model.modules(), False)
    # Test MobileNetV2 forward with widen_factor=1.0, pretrained
    model = MobileNetV2(
        widen_factor=1.0,
        out_indices=range(0, 8),
        pretrained='mmcls://mobilenet_v2')
    model.init_weights()
    model.train()
    assert check_norm_state(model.modules(), True)
    feat = model(imgs)
    assert len(feat) == 8
    assert feat[0].shape == torch.Size((1, 16, 112, 112))
    assert feat[1].shape == torch.Size((1, 24, 56, 56))
    assert feat[2].shape == torch.Size((1, 32, 28, 28))
    assert feat[3].shape == torch.Size((1, 64, 14, 14))
    assert feat[4].shape == torch.Size((1, 96, 14, 14))
    assert feat[5].shape == torch.Size((1, 160, 7, 7))
    assert feat[6].shape == torch.Size((1, 320, 7, 7))
    assert feat[7].shape == torch.Size((1, 1280, 7, 7))
    # Test MobileNetV2 forward with widen_factor=0.5
    model = MobileNetV2(widen_factor=0.5, out_indices=range(0, 7))
    model.init_weights()
    model.train()
    feat = model(imgs)
    assert len(feat) == 7
    assert feat[0].shape == torch.Size((1, 8, 112, 112))
    assert feat[1].shape == torch.Size((1, 16, 56, 56))
    assert feat[2].shape == torch.Size((1, 16, 28, 28))
    assert feat[3].shape == torch.Size((1, 32, 14, 14))
    assert feat[4].shape == torch.Size((1, 48, 14, 14))
    assert feat[5].shape == torch.Size((1, 80, 7, 7))
    assert feat[6].shape == torch.Size((1, 160, 7, 7))
    # Test MobileNetV2 forward with widen_factor=2.0
    model = MobileNetV2(widen_factor=2.0)
    model.init_weights()
    model.train()
    feat = model(imgs)
    assert feat.shape == torch.Size((1, 2560, 7, 7))
    # Test MobileNetV2 forward with out_indices=None
    model = MobileNetV2(widen_factor=1.0)
    model.init_weights()
    model.train()
    feat = model(imgs)
    assert feat.shape == torch.Size((1, 1280, 7, 7))
    # Test MobileNetV2 forward with dict(type='ReLU')
    model = MobileNetV2(
        widen_factor=1.0, act_cfg=dict(type='ReLU'), out_indices=range(0, 7))
    model.init_weights()
    model.train()
    feat = model(imgs)
    assert len(feat) == 7
    assert feat[0].shape == torch.Size((1, 16, 112, 112))
    assert feat[1].shape == torch.Size((1, 24, 56, 56))
    assert feat[2].shape == torch.Size((1, 32, 28, 28))
    assert feat[3].shape == torch.Size((1, 64, 14, 14))
    assert feat[4].shape == torch.Size((1, 96, 14, 14))
    assert feat[5].shape == torch.Size((1, 160, 7, 7))
    assert feat[6].shape == torch.Size((1, 320, 7, 7))
    # Test MobileNetV2 with GroupNorm forward
    model = MobileNetV2(widen_factor=1.0, out_indices=range(0, 7))
    for m in model.modules():
        if is_norm(m):
            assert isinstance(m, _BatchNorm)
    model.init_weights()
    model.train()
    feat = model(imgs)
    assert len(feat) == 7
    assert feat[0].shape == torch.Size((1, 16, 112, 112))
    assert feat[1].shape == torch.Size((1, 24, 56, 56))
    assert feat[2].shape == torch.Size((1, 32, 28, 28))
    assert feat[3].shape == torch.Size((1, 64, 14, 14))
    assert feat[4].shape == torch.Size((1, 96, 14, 14))
    assert feat[5].shape == torch.Size((1, 160, 7, 7))
    assert feat[6].shape == torch.Size((1, 320, 7, 7))
    # Test MobileNetV2 with BatchNorm forward
    model = MobileNetV2(
        widen_factor=1.0,
        norm_cfg=dict(type='GN', num_groups=2, requires_grad=True),
        out_indices=range(0, 7))
    for m in model.modules():
        if is_norm(m):
            assert isinstance(m, GroupNorm)
    model.init_weights()
    model.train()
    feat = model(imgs)
    assert len(feat) == 7
    assert feat[0].shape == torch.Size((1, 16, 112, 112))
    assert feat[1].shape == torch.Size((1, 24, 56, 56))
    assert feat[2].shape == torch.Size((1, 32, 28, 28))
    assert feat[3].shape == torch.Size((1, 64, 14, 14))
    assert feat[4].shape == torch.Size((1, 96, 14, 14))
    assert feat[5].shape == torch.Size((1, 160, 7, 7))
    assert feat[6].shape == torch.Size((1, 320, 7, 7))
    # Test MobileNetV2 with layers 1, 3, 5 out forward
    model = MobileNetV2(widen_factor=1.0, out_indices=(0, 2, 4))
    model.init_weights()
    model.train()
    feat = model(imgs)
    assert len(feat) == 3
    assert feat[0].shape == torch.Size((1, 16, 112, 112))
    assert feat[1].shape == torch.Size((1, 32, 28, 28))
    assert feat[2].shape == torch.Size((1, 96, 14, 14))
    # Test MobileNetV2 with checkpoint forward
    model = MobileNetV2(
        widen_factor=1.0, with_cp=True, out_indices=range(0, 7))
    for m in model.modules():
        if is_block(m):
            assert m.with_cp
    model.init_weights()
    model.train()
    feat = model(imgs)
    assert len(feat) == 7
    assert feat[0].shape == torch.Size((1, 16, 112, 112))
    assert feat[1].shape == torch.Size((1, 24, 56, 56))
    assert feat[2].shape == torch.Size((1, 32, 28, 28))
    assert feat[3].shape == torch.Size((1, 64, 14, 14))
    assert feat[4].shape == torch.Size((1, 96, 14, 14))
    assert feat[5].shape == torch.Size((1, 160, 7, 7))
    assert feat[6].shape == torch.Size((1, 320, 7, 7))