code: def _get_sub_package_provider_session(self, sub_package, session_name, proxy=None):
          
          agent_key = self._get_agent_key()
          if session_name in self._provider_sessions[agent_key]:
              return self._provider_sessions[agent_key][session_name]
          else:
              manager = self._get_sub_package_provider_manager(sub_package)
              session = self._instantiate_session('get_' + session_name + '_for_bank',
                                                  proxy=self._proxy,
                                                  manager=manager)
              self._set_bank_view(session)
              self._set_object_view(session)
              self._set_operable_view(session)
              self._set_containable_view(session)
              if self._session_management != DISABLED:
                  self._provider_sessions[agent_key][session_name] = session
              return session
docs: Gets the session from a sub-package