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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 _banner_default(self):
 """ Reimplement banner creation to let the user decide if he wants a banner or not """

        # Don't change banner for external kernels
        if self.external_kernel:
            return ''
        show_banner_o = self.additional_options['show_banner']
        if show_banner_o:
            return self.long_banner()
        else:
            return self.short_banner()