Python classes has a __str__ attribute and a __repr__ attribute such that if you use print(model) you will get a string.
If you have a class inherited from a nn.Module and you print an instance of that class you will get a list of the layers sorted in the same way you defined them and with the name you used to define the layers inside the nn.Module.
So basically if you have
class Audio_Model(nn.Module):
    def __init__(self):
        super(Audio_Model, self).__init__()
        self.watermelon = nn.Linear(A,B)

Watermelon will appear when you do
model = Audio_Model()
print(model)

If you give a meaningful name, then that name will appear.