code: def _do_highlight(content, query, tag='em'):
          
          for term in query:
              term = term.decode('utf-8')
              for match in re.findall('[^A-Z]+', term):  # Ignore field identifiers
                  match_re = re.compile(match, re.I)
                  content = match_re.sub('<%s>%s</%s>' % (tag, term, tag), content)
  
          return content
docs: Highlight `query` terms in `content` with html `tag`.
  
          This method assumes that the input text (`content`) does not contain
          any special formatting.  That is, it does not contain any html tags
          or similar markup that could be screwed up by the highlighting.
  
          Required arguments:
              `content` -- Content to search for instances of `text`
              `text` -- The text to be highlighted