ChartGridLines
Configures the appearance of horizontal and vertical grid lines within the chart.
ChartGridLines class has the following properties:
color
 The color of a grid line.
dash_pattern
 Defines dash effect of the line. The value is a circular list of dash offsets and lengths. For example, the list [5, 10] would result in dashes 5 pixels long followed by blank spaces 10 pixels long. By default, a solid line is drawn.
interval
 The interval between grid lines.
Defaults to 1.
width
 The width of a grid line.
Defaults to 1.