Satisfy trait type condition

src/di_multigraph_adjlist.jl

@@ -165,6 +165,7 @@ function mul(mg::DiMultigraph, s::Integer, d::Integer)
 end
 
 is_directed(mg::DiMultigraph) = true
+is_directed(mg::Type{<:DiMultigraph}) = true
 function ne(mg::DiMultigraph; count_mul::Bool = false)
     if count_mul
         return sum([length(mg.adjlist[v]) for v in vertices(mg)])

src/multigraph_adjlist.jl

@@ -152,6 +152,7 @@ function mul(mg::Multigraph, s::Integer, d::Integer)
 end
 
 is_directed(mg::Multigraph) = false
+is_directed(mg::Type{<:Multigraph}) = false
 function ne(mg::Multigraph; count_mul::Bool = false)
     if count_mul
         return sum([sum(mg.adjlist[v] .>= v) for v in vertices(mg)])

test/di_multigraph_adjlist.jl

@@ -40,6 +40,7 @@ g1 = DiMultigraph(path_digraph(3))
 @test adjacency_matrix(g) == m
 
 @test is_directed(g)
+@test is_directed(typeof(g))
 @test edgetype(g) == MultipleEdge{Int, Int}
 @test size(adjacency_matrix(g), 1) == 4
 
@@ -72,4 +73,4 @@ add_vertex!(g)
 @test indegree(g) != outdegree(g)
 
 dmg0 = DiMultigraph(0)
-@test nv(dmg0) == ne(dmg0) == 0
+@test nv(dmg0) == ne(dmg0) == 0

test/multigraph_adjlist.jl

@@ -39,6 +39,7 @@ g1 = Multigraph(path_graph(3))
 @test adjacency_matrix(g) == m
 
 @test !is_directed(g)
+@test !is_directed(typeof(g))
 @test edgetype(g) == MultipleEdge{Int, Int}
 @test size(adjacency_matrix(g), 1) == 4
 
@@ -68,4 +69,4 @@ add_vertex!(g)
 @test indegree(g) == outdegree(g)
 
 mg0 = Multigraph(0)
-@test nv(mg0) == ne(mg0) == 0
+@test nv(mg0) == ne(mg0) == 0