src/transformers/models/deberta_v2/modeling_tf_deberta_v2.py/pos_dynamic_expand
def pos_dynamic_expand(pos_index, p2c_att, key_layer):
    shapes = shape_list(p2c_att)[:2] + [shape_list(pos_index)[-2], shape_list(key_layer)[-2]]
    return tf.broadcast_to(pos_index, shapes)