我正在将julia 0.6的代码转换为1.2。 这是旧版本：

@variable(model,use[i=eachindex(n),j=1:m],Bin)

Used  = [indmax(getvalue(use[i,j])
                           for j=1:m) for i=eachindex(n)]

我转换为以下内容，

@variable(model,Bin)

JuMP.optimize!(model)
Used = [argmax(JuMP.value(use[i,j])
                    for j=1:m) for i=eachindex(n)]

但有错误：

MethodError: no method matching keys(::Base.Generator{UnitRange{Int64},getfield(Main,Symbol("##261#266")){Int64,JuMP.Containers.SparseAxisArray{VariableRef,2,Tuple{Any,Any}}}})
Closest candidates are:
  keys(!Matched::Core.SimpleVector) at essentials.jl:606
  keys(!Matched::Cmd) at process.jl:963
  keys(!Matched::BenchmarkTools.BenchmarkGroup) at /Users/shuaiwang/.julia/packages/BenchmarkTools/7aqwe/src/groups.jl:31
  ...
pairs(::Base.Generator{UnitRange{Int64},Any}}}}) at abstractdict.jl:132
_findmax(::Base.Generator{UnitRange{Int64},Any}}}},::Colon) at array.jl:2068
findmax(::Base.Generator{UnitRange{Int64},Any}}}}) at array.jl:2065
argmax(::Base.Generator{UnitRange{Int64},Any}}}}) at array.jl:2153
(::getfield(Main,Symbol("##260#265")){ScenarioGraph,Any}}})(::Int64) at none:0
iterate at generator.jl:47 [inlined]
collect at array.jl:606 [inlined]