docs: def with_env(self, **environment_variables):
          """
          Return new Command object that will be run with additional
          environment variables.
  
          Specify environment variables as follows:
  
              new_cmd = old_cmd.with_env(PYTHON_PATH=".", ENV_PORT="2022")
          """
          new_env_vars = {
              str(var): str(val) for var, val in environment_variables.items()
          }
          new_command = copy.deepcopy(self)
          new_command._env.update(new_env_vars)
          return new_command