The dtype of attention mask (torch.int64) is not bool

This error message indicates that the data type of the attention mask tensor is `torch.int64`, but it should be `bool`.

To fix this, you can convert the tensor to the correct data type using the `.bool()` method. For example, if your attention mask tensor is called `attention_mask`, you can convert it to `bool` by doing:

attention_mask = attention_mask.bool()

After this conversion, your attention mask tensor should have the correct data type and the error should be resolved.