code: def merge(src, dst, debug):
      """
      Merges existing datasets into a single one.
      """
  
      if debug:
          tf.logging.set_verbosity(tf.logging.DEBUG)
      else:
          tf.logging.set_verbosity(tf.logging.INFO)
  
      tf.logging.info('Saving records to "{}"'.format(dst))
      writer = tf.python_io.TFRecordWriter(dst)
  
      total_records = 0
  
      for src_file in src:
          total_src_records = 0
          for record in tf.python_io.tf_record_iterator(src_file):
              writer.write(record)
              total_src_records += 1
              total_records += 1
  
          tf.logging.info(
              'Saved {} records from "{}"'.format(
                  total_src_records, src_file
              )
          )
  
      tf.logging.info('Saved {} to "{}"'.format(total_records, dst))
  
      writer.close()
  
label_desc: Use image node_id 1 for calling a global function with example usage: merge(src, dst, debug) without return types