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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def quote(identifier, html=HTML_STRING.match, valid_id=ID.match, dot_keywords=KEYWORDS):
 """Return DOT identifier from string, quote if needed. '""' 'spam' '"spam spam"' '-4.2' '.42' '<<b>spam</b>>' '"<>"' """

    if html(identifier) and not isinstance(identifier, NoHtml):
        pass
    elif not valid_id(identifier) or identifier.lower() in dot_keywords:
        return '"%s"' % identifier.replace('"', '\\"')
    return identifier