I have a question
When training using BertForMaskedLM, is the train data as below correct?

token2idx

<pad> : 0, <mask>: 1, <cls>:2, <sep>:3


max len : 8
input token

 <cls> hello i <mask> cats <sep>


input ids

 [2, 34,45,1,56,3,0,0]


attention_mask

 [1,1,1,1,1,1,0,0]


labels

 [-100,-100,-100,64,-100,-100,-100,-100]

I wonder if I should also assign -100 to labels for padding token.