'Instruct all contained L{sxbasic.Import} children to import
the schema\'s which they reference.  The contents of the
imported schema are I{merged} in.
@param options: An options dictionary.
@type options: L{options.Options}'

def open_imports(self, options):

    for imp in self.imports:
        imported = imp.open(options)
        if (imported is None):
            continue
        imported.open_imports(options)
        log.debug('imported:\n%s', imported)
        self.merge(imported)
