'@param ref: The schema reference being queried.
@type ref: qref'

def __init__(self, ref=None):

    Object.__init__(self)
    self.id = objid(self)
    self.ref = ref
    self.history = []
    self.resolved = False
    if (not isqref(self.ref)):
        raise Exception(('%s,    must    be    qref' % tostr(self.ref)))
