def preprocess(source):
doc = html5lib.parseFragment(source)<EOL>source = ET.tostring(doc, encoding='<STR_LIT:utf-8>', method='<STR_LIT:text>').decode('<STR_LIT:utf-8>')<EOL>source = source.replace(u'<STR_LIT:\n>', u'<STR_LIT>').strip()<EOL>source = re.sub(r'<STR_LIT>', u'<STR_LIT:U+0020>', source)<EOL>return source<EOL>
Removes unnecessary break lines and white spaces.

    Args:
      source (str): Input sentence.

    Returns:
      Preprocessed sentence. (str)