text: var nodes = new vis.DataSet([
                               /* {id: a, label: b, ...}, */
  {id: '1900', label: 'D5\nexpected', color: '#31b0d5', title: 'Name: D5<br>Alias: null<br>Value: expected<br>Type: CELL_WITH_FORMULA<br>Id: 1900<br>Formula Expression: Formula String: T(D2); Formula Values: T(expected); Formula Ptg: ; Ptgs:  Index in Ptgs: 0 <br>Source Object Id: com.dataart.spreadsheetanalytics.engine.PoiProxyWorkbook@234c5e41'},
  {id: '1901', label: 'D2\nexpected', color: '#31b0d5', title: 'Name: D2<br>Alias: null<br>Value: expected<br>Type: CELL_WITH_VALUE<br>Id: 1901<br>Formula Expression: Formula String: D2; Formula Values: expected; Formula Ptg: expected; Ptgs: D2 Index in Ptgs: 0 <br>Source Object Id: com.dataart.spreadsheetanalytics.engine.PoiProxyWorkbook@234c5e41'},
  {id: '1902', label: 'T\nexpected', color: '#f0ad4e', title: 'Name: T<br>Alias: null<br>Value: expected<br>Type: FUNCTION<br>Id: 1902<br>Formula Expression: Formula String: T(D2); Formula Values: T(expected); Formula Ptg: ; Ptgs:  Index in Ptgs: 1 <br>Source Object Id: com.dataart.spreadsheetanalytics.engine.PoiProxyWorkbook@234c5e41'}
                              ]);
  
  
  var edges = new vis.DataSet([
                               /* {from: id_a, to: id_b}, */
  {from: '1901', to: '1902'},
  {from: '1902', to: '1900'}
                              ]);