Chart multiple series from a column distinct values

def _multiseries(self, col, x, y, ctype, rsum, rmean):
		"""
		Chart multiple series from a column distinct values
		"""
		self.autoprint = False
		x, y = self._check_fields(x, y)
		chart = None
		series = self.split_(col)
		for key in series:
			instance = series[key]
			if rsum is not None:
				instance.rsum(rsum, index_col=x)
			if rmean is not None:
				instance.rmean(rmean, index_col=x)
			instance.chart(x, y)
			self.scolor()
			c = None
			label = str(key)
			if ctype == "point":
				c = instance.point_(label)
			if ctype == "line":
				instance.zero_nan(y)
				c = instance.line_(label)
			if ctype == "bar":
				c = instance.bar_(label)
			if ctype == "area":
				c = instance.area_(label)
			if c is None:
				self.warning("Chart type " + ctype + 
							 " not supported, aborting")
				return
			if chart is None:
				chart = c
			else:
				chart = chart * c
		return chart