Get an stacked area chart

def sarea_(self, col, x=None, y=None, rsum=None, rmean=None):
		"""
		Get an stacked area chart
		"""
		try:
			charts = self._multiseries(col, x, y, "area", rsum, rmean)
			return hv.Area.stack(charts)
		except Exception as e:
			self.err(e, self.sarea_, "Can not draw stacked area chart")