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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 ngettext(self, singular, plural, num, domain=None, **variables):
 """Translate a string wity the current locale. The `num` parameter is used to dispatch between singular and various plural forms of the message. """

        variables.setdefault('num', num)
        t = self.get_translations(domain)
        return t.ungettext(singular, plural, num) % variables