Sequential.py

class Sequential(Module):
    """ Special instance of neural network which can be constructed as a sequence of layers
    """
    def __init__(self, *modules):
        self._modules = list(modules)

    def forward(self, X):
        for module in self._modules:
            X = module.forward(X)
        return X

    def backward(self, output_grad):
        for module in reversed(self._modules):
            output_grad = module.backward(output_grad)
        return output_grad

    def has_parameters(self, module):
        return True if isinstance(module, (Linear, Conv2d, BatchNorm2d)) else False

    def step(self, optimizer):
        for module in self._modules:
            if self.has_parameters(module):
                module.step(optimizer)