def _get_css_imports_regex(data):
 urls = []
 for pattern in _CSS_URL_PATTERNS:
  for match in pattern.finditer(data):
   url = match.group('url')
   if url:
    urls.append(url)
 return urls

def _get_css_imports_regex ( data ) : urls = [ ] for pattern in _CSS_URL_PATTERNS : for match in pattern . finditer ( data ) : url = match . group ( 'url' ) if url : urls . append ( url ) return urls
return all assets that are referenced in the given css document .