code: def chart_type(self, value):
          
          if value not in self._allowed_charts:
              raise ValueError("Not a valid chart type")
  
          self.options["chart_type"] = value
docs: 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.