TheModelClass is just a placeholder name for your model class name.
E.g. you can define your model as:
class MyModel(nn.Module):
    def __init__(self):
        super(MyModel, self).__init__()
        self.fc1 = nn.Linear(1, 1)
 
    def forward(self, x):
        return self.fc1(x)

model = MyModel()
model.load_state_dict(torch.load(PATH))

In that case, you would be using MyModel as the class name instead of TheModelClass.