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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 set_html5_doctype(self):
 """Method used to transform a doctype in to a properly html5 doctype """

        doctype = b'<!DOCTYPE html>\n'
        content = doctype_re.subn(doctype, self.response.content, 1)[0]
        self.response.content = content