src/transformers/models/nystromformer/modeling_nystromformer.py/NystromformerAttention/forward
class NystromformerAttention:    def forward(self, hidden_states, attention_mask=None, output_attentions=False):
        self_outputs = self.self(hidden_states, attention_mask, output_attentions)
        attention_output = self.output(self_outputs[0], hidden_states)
        outputs = (attention_output,) + self_outputs[1:]  # add attentions if we output them
        return outputs