def METHOD_NAME(self, root):
    """
    Apply the import (rule) to the specified schema.
    If the schema does not already contain an import for the
    I{namespace} specified here, it is added.
    @param root: A schema root.
    @type root: L{Element}
    """
    if not self.filter.match(root, self.ns):
        return
    if self.exists(root):
        return
    node = Element('import', ns=self.xsdns)
    node.set('namespace', self.ns)
    if self.location is not None:
        node.set('schemaLocation', self.location)
    log.debug('inserting: %s', node)
    root.insert(node)