AttributeError: module ‘torch.nn‘ has no attribute ‘module‘

import torch 
import torch.nn as nn

class LinearModel(nn.Module):
    def _init_(self,ndim):
        super(LinearModel,self)._init_()
        self.ndim=ndim
        
        self.weight=nn.Parameter(torch.randn(ndim,1))#定义权重
        self.bias=nn.Parameter(torch.randn(1)) #定义偏置
         
    def forward(self,x):
    # y = wx +b
        return x.mm(self.weight)+self.bias

lm=LinearModel(5)

如上，调用时报错：
init() takes 1 positional argument but 2 were given

纠错发现是少打了下划线

init前后有两个_,