def _add_agents(self, agent_definitions):
        """Add specified agents to the client. Set up their shared memory and sensor linkages.
        Does not spawn an agent in the Holodeck, this is only for documenting and accessing already existing agents.
        This is an internal function.
        Positional Arguments:
        agent_definitions -- The agent(s) to add.
        """
        if not isinstance(agent_definitions, list):
            agent_definitions = [agent_definitions]
        prepared_agents = self._prepare_agents(agent_definitions)
        self._all_agents.extend(prepared_agents)
        for agent in prepared_agents:
            self.agents[agent.name] = agent
        for agent in agent_definitions:
            self.add_state_sensors(agent.name, [Sensors.TERMINAL, Sensors.REWARD])
            self.add_state_sensors(agent.name, agent.sensors)
Add specified agents to the client. Set up their shared memory and sensor linkages.
        Does not spawn an agent in the Holodeck, this is only for documenting and accessing already existing agents.
        This is an internal function.
        Positional Arguments:
        agent_definitions -- The agent(s) to add.