Set the MetricsGraphics chart type.
            Allowed charts are: line, histogram, point, and bar

            Args:
                value (str): chart type.

            Raises:
                ValueError: Not a valid chart type.

def chart_type(self, value):
        """Set the MetricsGraphics chart type.
            Allowed charts are: line, histogram, point, and bar

            Args:
                value (str): chart type.

            Raises:
                ValueError: Not a valid chart type.
        """
        if value not in self._allowed_charts:
            raise ValueError("Not a valid chart type")

        self.options["chart_type"] = value