custom a tooltipContent of tooltips with datum in discreteBarChart nvd3.js-open source projects novus/nvd3

How I can custom a tooltipContent of tooltips using data loaded into “datum” in discreteBarChart nvd3.js?, for example, with the following data Jason, I want to see data3, data4, Data5 in tooltips

JsonData = [ 
             {
               key: "Serie1",
               values: [
                         {'Data1':  1, 
                          'Data2':  2, 
                          'Data3':  3,
                          'Data4':  4,
                          'Data5':  5
                         }
                       ]
             }
           ];