Dijkstra:88: attempt to index local 'e' (a number value)

[DavidSheh]

local g = require('luagraphs.data.graph').create(8); -- undirected weighted graph

g:addEdge(5, 4, 72)
g:addEdge(9, 8, 73)
g:addEdge(11, 12, 66)
g:addEdge(22, 11, 48)
g:addEdge(20, 19, 34)
g:addEdge(6, 5, 56)
g:addEdge(4, 3, 76)
g:addEdge(21, 6, 18)
g:addEdge(13, 17, 47)
g:addEdge(21, 20, 37)
g:addEdge(9, 10, 61)
g:addEdge(21, 22, 102)
g:addEdge(10, 11, 65)
g:addEdge(2, 3, 85)
g:addEdge(7, 6, 82)
g:addEdge(15, 16, 43)
g:addEdge(2, 1, 74)
g:addEdge(14, 1, 48)
g:addEdge(18, 17, 71)
g:addEdge(15, 14, 47)
g:addEdge(7, 8, 71)
g:addEdge(19, 4, 121)
g:addEdge(19, 16, 61)
g:addEdge(19, 18, 64)
g:addEdge(12, 13, 24)

local source = 6
local dijkstra = require('luagraphs.shortest_paths.Dijkstra').create()
dijkstra:run(g, source) -- source is the id of the source node in the path search
local path = dijkstra:getPathTo(10)

Use the above test data to report an error。error message is :

Dijkstra:88: attempt to index local 'e' (a number value)