docs: def populate_menv(menv, agent_cls_name, log_folder):
      '''Populate given multiprocessing grid environment with agents.
  
      :param menv: Instance of :py:class:`GridMultiEnvironment`
      :param str agent_cls_name: Name of the agent class, e.g. 'grip_mp:GridAgent'
      :param str log_folder: Root logging folder for the agents.
      '''
      gs = menv.gs
      n_agents = gs[0] * gs[1]
      n_slaves = len(menv.addrs)
      logger.info("Populating {} with {} agents".format(HOST, n_agents*n_slaves))
      run(menv.populate(agent_cls_name, n_agents, log_folder=log_folder))
      logger.info("Populating complete.")