see the code below, when there is no transport, why do we give a no_implement, shouldn't it be nocontext in the first two throws?

    /// Obtains the IIOP_Connection_Handler associated with the
    /// Transport. Will throw NO_IMPLEMENT if the (selected) transport
    /// () == 0, or if transport->connection_handler () == 0. Will
    /// throw NoContext, if no transport has been selected yet.
    TAO_IIOP_Connection_Handler*
    IIOP_Current_Impl::handler (void)
    {
#if defined (TAO_HAS_IIOP) && (TAO_HAS_IIOP != 0)
      const TAO_Transport* t = this->transport ();
      if (t == 0)
        throw ::CORBA::NO_IMPLEMENT ();

      TAO_Connection_Handler *ch = const_cast<TAO_Transport*>(t)->connection_handler ();
      if (ch == 0)
        throw ::CORBA::NO_IMPLEMENT ();

      return dynamic_cast <TAO_IIOP_Connection_Handler*> (ch);
#else
      throw ::CORBA::NO_IMPLEMENT ();
#endif
    }