src/transformers/models/lxmert/modeling_lxmert.py/LxmertCrossAttentionLayer/forward
class LxmertCrossAttentionLayer:    def forward(self, input_tensor, ctx_tensor, ctx_att_mask=None, output_attentions=False):
        output = self.att(input_tensor, ctx_tensor, ctx_att_mask, output_attentions=output_attentions)
        if output_attentions:
            attention_probs = output[1]
        attention_output = self.output(output[0], input_tensor)
        outputs = (attention_output, attention_probs) if output_attentions else (attention_output,)
        return outputs