'@param instance: The instance to look up.
@param incref: Flag to specify whether to increment the
reference.
@return: An ID that says what this instance is cached as
remotely, or L{None} if it\'s not.'

def cachedRemotelyAs(self, instance, incref=0):

    puid = instance.processUniqueID()
    luid = self.remotelyCachedLUIDs.get(puid)
    if ((luid is not None) and incref):
        self.remotelyCachedObjects[luid].incref()
    return luid
