docstr: Change the phase of the environment
  :param val: the new phase
  :return: None
code: def phase(self, val: RunPhase):
      """
      Change the phase of the environment
      :param val: the new phase
      :return: None
      """
      self._phase = val
  
file_path: coach/rl_coach/environments/environment_interface.py
imports: from typing import Union, Dict
  from rl_coach.core_types import ActionType, EnvResponse, RunPhase
  from rl_coach.spaces import ActionSpace
label_desc: Use image node_id 3 for calling the EnvironmentInterface obj's underlying member method code with example usage: obj.phase(val) without return types