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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 rebase(self, text, char='X'):
 """ Rebases text with stop words removed. """

        regexp = re.compile(r'\b(%s)\b' % '|'.join(self.collection),
                            re.IGNORECASE | re.UNICODE)

        def replace(m):
            word = m.group(1)
            return char * len(word)

        return regexp.sub(replace, text)