# Module: tf_agents.trajectories.time_step
|---| | [![](https://www.tensorflow.org/images/GitHub-Mark-32px.png) View source on GitHub](https://github.com/tensorflow/agents/blob/v0.19.0/tf_agents/trajectories/time_step.py) | TimeStep representing a step in the environment. ## Classes [`class StepType`](https://www.tensorflow.org/agents/api_docs/python/tf_agents/trajectories/StepType): Defines the status of a `TimeStep` within a sequence. [`class TimeStep`](https://www.tensorflow.org/agents/api_docs/python/tf_agents/trajectories/TimeStep): Returned with every call to `step` and `reset` on an environment. ## Functions [`restart(...)`](https://www.tensorflow.org/agents/api_docs/python/tf_agents/trajectories/restart): Returns a `TimeStep` with `step_type` set equal to [`StepType.FIRST`](https://www.tensorflow.org/agents/api_docs/python/tf_agents/trajectories/StepType#FIRST). [`termination(...)`](https://www.tensorflow.org/agents/api_docs/python/tf_agents/trajectories/termination): Returns a `TimeStep` with `step_type` set to [`StepType.LAST`](https://www.tensorflow.org/agents/api_docs/python/tf_agents/trajectories/StepType#LAST). [`time_step_spec(...)`](https://www.tensorflow.org/agents/api_docs/python/tf_agents/trajectories/time_step_spec): Returns a `TimeStep` spec given the observation_spec. [`transition(...)`](https://www.tensorflow.org/agents/api_docs/python/tf_agents/trajectories/transition): Returns a `TimeStep` with `step_type` set equal to [`StepType.MID`](https://www.tensorflow.org/agents/api_docs/python/tf_agents/trajectories/StepType#MID). [`truncation(...)`](https://www.tensorflow.org/agents/api_docs/python/tf_agents/trajectories/truncation): Returns a `TimeStep` with `step_type` set to [`StepType.LAST`](https://www.tensorflow.org/agents/api_docs/python/tf_agents/trajectories/StepType#LAST).


| ## Other Members || |---|---| | absolute_import | Instance of `__future__._Feature` | | division | Instance of `__future__._Feature` | | print_function | Instance of `__future__._Feature` |