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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 _altair_line_num_(self, xfield, yfield, opts, style, encode):
 """ Get a line + text number chart """

        try:
            c = self._altair_chart_num_("line", xfield,
                                           yfield, opts, style, encode)
        except Exception as e:
            self.err(e, "Can not draw a line num chart")
            return
        return c