code: def sline_(self, window_size=5,
  			   y_label="Moving average", chart_label=None):
  		
  		options = dict(window_size=window_size, y_label=y_label)
  		try:
  			return self._get_chart("sline", style=self.chart_style,
  								   opts=self.chart_opts, label=chart_label,
  								   options=options)
  		except Exception as e:
  			self.err(e, self.sline_, "Can not draw smooth curve chart")
docs: Get a moving average curve chart to smooth between points