'Scan the given multilang (UDL-based) buffer and return a CIX
element tree.
"buf" is the multi-lang UDLBuffer instance (e.g.
lang_rhtml.RHTMLBuffer for RHTML).
"csl_cile_driver" (optional) is the CSL (client-side language)
CILE driver. While scanning, CSL tokens should be gathered and,
if any, passed to the CSL scanner like this:
csl_cile_driver.scan_csl_tokens(
file_elem, blob_name, csl_tokens)
The CSL scanner will append a CIX <scope ilk="blob">
element to the <file> element.
A language that supports being part of a multi-lang document
must implement this method.'

def scan_multilang(self, buf, csl_cile_driver=None):

    raise VirtualMethodError('CILEDriver.scan_multilang')
