src/transformers/models/longformer/modeling_tf_longformer.py/TFLongformerClassificationHead/call
class TFLongformerClassificationHead:    def call(self, hidden_states, training=False):
        hidden_states = hidden_states[:, 0, :]  # take <s> token (equiv. to [CLS])
        hidden_states = self.dropout(hidden_states, training=training)
        hidden_states = self.dense(hidden_states)
        hidden_states = self.dropout(hidden_states, training=training)
        output = self.out_proj(hidden_states)
        return output