code: def build(self, hp, inputs=None):
      input_node = nest.flatten(inputs)[0]
      output_node = input_node
      output_node = basic.RNNBlock().build(hp, output_node)
      return output_node
  
imports: from typing import Optional
  from tensorflow import nest
  from autokeras.blocks import basic
  from autokeras.blocks import preprocessing
  from autokeras.blocks import reduction
  from autokeras.engine import block
label_desc: Use image node_id 3 for calling the TimeseriesBlock obj's underlying member method code with example usage: obj.build(hp, inputs) and returns: output_node