Frappe Charts in Report using frappe.call

Hi,

I am trying to build chart in query report, chart data isn’t relevant to report data, thats why i am using frappe.call method to get data using python.

i’ve python function which is returning labels and datasets,
but when i am calling it using frappe.call the report page shows blank page.

here is my code

get_chart_data: function(columns, result) {
	return {    	        
	        frappe.call({
    			method: "erpnext.projects.doctype.project_details.project_details.summary",
    			callback: function(r) {
    	      		data: r.message,
    				
    				type: 'pie', // or 'bar', 'line', 'pie', 'percentage'
        	                        height: 300
    			}
    		});
		}    		
	}

anybody?