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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 stem(self, s):
 """ Performs stemming on the string. :param s: the string to stem :type s: str :return: the stemmed string :rtype: str """

        return javabridge.get_env().get_string(self.__stem(javabridge.get_env().new_string_utf(s)))