Need to be able to form Open versions of InterType acsets

[p-stokes]

It would be good to be able to form open versions of intertype acsets. Currently, using the output constructors from OpenACSetTypes doesn't appear to work, as in the weighted graphs example below. (Note that OpenCSetTypes does appear to work for plain graphs.)

The following example for weighted graphs (which uses the wgraph.it file from the tests) errors:

using ACSets.InterTypes
@intertypes "wgraph.it" module wgraph end
using .wgraph
OpenITWGraphOb, OpenITWGraph = OpenACSetTypes(wgraph.WeightedGraph, :V)
g0′ = wgraph.EDWeightedGraph()
add_parts!(g0′, :V, 2)
add_part!(g0′, :E, src=1, tgt=2, weight=wgraph.EdgeData(:mass, 5))
g′ = OpenITWGraph{UInt64}(g0′, FinFunction([1],2), FinFunction([2],2))

The error is:

g′ = OpenITWGraph{UInt64}(g0′, FinFunction([1],2), FinFunction([2],2))
ERROR: MethodError: no method matching coerce_attrvar_component(::Symbol, ::UnitRange{Int64}, ::TypeSet{UInt64}, ::TypeSet{Main.wgraph.EdgeData}, ::Int64, ::Int64)

Closest candidates are:
  coerce_attrvar_component(::Symbol, ::AbstractVector, ::TypeSet{T}, ::TypeSet{T}, ::Int64, ::Int64) where T
   @ Catlab ~/.julia/packages/Catlab/ARIR5/src/categorical_algebra/CSets.jl:452
  coerce_attrvar_component(::Symbol, ::LooseVarFunction, ::TypeSet{T}, ::TypeSet{T′}, ::Int64, ::Int64) where {T, T′}
   @ Catlab ~/.julia/packages/Catlab/ARIR5/src/categorical_algebra/CSets.jl:468
  coerce_attrvar_component(::Symbol, ::Function, ::TypeSet{T}, ::TypeSet{T′}, ::Int64, ::Int64) where {T, T′}
   @ Catlab ~/.julia/packages/Catlab/ARIR5/src/categorical_algebra/CSets.jl:480
  ...

For comparison, the non-intertype version (obviously) works.

using Catlab.GATs, Catlab.Theories, Catlab.Graphs, Catlab.CategoricalAlgebra
const OpenWeightedGraphOb, OpenWeightedGraph = OpenACSetTypes(WeightedGraph, :V)
g0 = WeightedGraph{Float64}(2)
add_edge!(g0, 1, 2, weight=1.5)
g = OpenWeightedGraph{Float64}(g0, FinFunction([1],2), FinFunction([2],2))