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Solve the following problem using Python, implementing the functions described below, one line at a time
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<USER_TASK:>
Description:
 def strip_tweet(text, remove_url=True):
 """Strip tweet message. This method removes mentions strings and urls(optional). :param text: tweet message :type text: :class:`str` :param remove_url: Remove urls. default :const:`True`. :type remove_url: :class:`boolean` :returns: Striped tweet message :rtype: :class:`str` """

    if remove_url:
        text = url_pattern.sub('', text)
    else:
        text = expand_url(text)
    text = mention_pattern.sub('', text)
    text = html_parser.unescape(text)
    text = text.strip()
    return text