Get a stacked bar chart

def sbar_(self, stack_index=None, label=None, style=None, opts=None,
			  options={}):
		"""
		Get a stacked bar chart
		"""
		self.opts(dict(stack_index=stack_index, color_index=stack_index))
		try:
			if stack_index is None:
				self.err(self.sbar_, "Please provide a stack index parameter")
			options["stack_index"] = stack_index
			return self._get_chart("bar", style=style, opts=opts, label=label,
								   options=options)
		except Exception as e:
			self.err(e, self.sbar_, "Can not draw stacked bar chart")