(Optional) A plain object with properties: customWarning [type: String, optional: true] - Custom text to explain why there is no data. customImageUrl [type: String, optional: true] - Custom image URL to be used. isSimplificationWarning [type: Boolean, optional: true] - Indicates there is no data because of a problem with simplifying it. isTransparent [type: Boolean, optional: true] - Indicates that the background should be semi-transparent.