
                    {
                        source: 'b',
                        target: 'b1',
                        value: 8
                    },
                    {
                        source: 'a',
                        target: 'b1',
                        value: 3
                    },
                    {
                        source: 'b1',
                        target: 'a1',
                        value: 1
                    },
                    {
                        sourc