like--a list for storing "Module" s! On the other hand, the layers
   in a "Sequential" are connected in a cascading way.
Example:
  # Using Sequential to create a small model. When `model` is run,
  # input will first be passed to `Conv2d(1,20,5)`. The output of
  # `Conv2d(1,20,5)` will be used as the input to the first
  # `ReLU`; the output of the first `ReLU` will become the input
  # for `Conv2d(20,64,5)`. Finally, the output of
  # `Conv2d(20,64,5)` will be used as input to the second `ReLU`
  model = nn.Sequential(
            nn.Conv2d(1,20,5),
            nn.ReLU(),
            nn.Conv2d(20,64,5),
            nn.ReLU()
          )

  # Using Sequential with OrderedDict. This is functionally the
  # same as the above code
  model = nn.Sequential(OrderedDict([
            ('conv1', nn.Conv2d(1,20,5)),
            ('relu1', nn.ReLU()),
            ('conv2', nn.Conv2d(20,64,5)),
            ('relu2', nn.ReLU())
