为什么我们要把nn.Module作为参数传递给神经网络的类定义?

我想理解为什么我们在定义像GAN这样的神经网络的类时,要传递torch.nn.Module作为参数

import torch
import torch.nn as nn

class Generator(nn.Module):
    def __init__(self, input_size, hidden_size, output_size, f):
        super(Generator, self).__init__()
        self.map1 = nn.Linear(input_size, hidden_size)
        self.map2 = nn.Linear(hidden_size, hidden_size)
        self.map3 = nn.Linear(hidden_size, output_size)
        self.f = f