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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 bleach_clean(stream):
 """ Sanitize malicious attempts but keep the `EXCERPT_TOKEN`. By default, only keeps `bleach.ALLOWED_TAGS`. """

    return bleach.clean(
        stream,
        tags=current_app.config['MD_ALLOWED_TAGS'],
        attributes=current_app.config['MD_ALLOWED_ATTRIBUTES'],
        styles=current_app.config['MD_ALLOWED_STYLES'],
        strip_comments=False)