class_docstr: Basically a list of TimeSteps with convenience methods.
class_docstr_tok: ["Basically","a","list","of","TimeSteps","with","convenience","methods","."]
code: def __str__(self):
      if not self.time_steps:
          return "Trajectory[]"
      return "Trajectory[{}]".format(
          ", ".join(str(ts) for ts in self.time_steps)
      )
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import os
  import pickle
  import re
  import sys
  import time
  from absl import logging
  import cloudpickle
  import numpy
  from tensor2tensor.envs import time_step
  import tensorflow.compat.v1
label_desc: Use image node_id 2 for calling the Trajectory obj's underlying member method code with example usage: obj.__str__() and returns: str, str