'@param l: The list of object which may contain some not yet referenced
objects.
@param containerType: A type of container objects (e.g., C{tuple} or
C{set}).'

def __init__(self, l, containerType):

    NotKnown.__init__(self)
    self.containerType = containerType
    self.l = l
    self.locs = list(range(len(l)))
    for idx in range(len(l)):
        if (not isinstance(l[idx], NotKnown)):
            self.locs.remove(idx)
        else:
            l[idx].addDependant(self, idx)
    if (not self.locs):
        self.resolveDependants(self.containerType(self.l))
