I have a class env_top, inside that I have env, env,env instantiated. Inside each env, I have sub_envA, sub_envB,sub_envC and the sub_env's are extended from a sub_env_base. Now, how can I identify from my sub_env_base, that I am under env or  or ?. The sub_env_base and env_top are extended from same top, say my_ovm_env_top. I need this info inside the sub_env_base, to get the VIFs from the corresponding env instance - env / env/ env.