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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 get_urls(self):
 """ Add a preview URL. """

        from django.conf.urls import patterns, url
        urls = super(RecurrenceRuleAdmin, self).get_urls()
        my_urls = patterns(
            '',
            url(
                r'^preview/$',
                self.admin_site.admin_view(self.preview),
                name='icekit_events_recurrencerule_preview'
            ),
        )
        return my_urls + urls