def loadFile(filename, reload=False, policy=u''):
    """Return an IModel as contained in the given XML file, which is read
        relative to the current module (unless it is an absolute path).

        If reload is True, reload a schema even if it's cached. If policy
        is given, it can be used to select a custom schema parsing policy.
        Policies must be registered as named utilities providing
        ISchemaPolicy.
        """
