refactor:Simpler code.

Author: antononcube

lib/Graph/Relation.rakumod

@@ -7,15 +7,16 @@ use Graph;
 class Graph::Relation is Graph {
     multi method new(&f, @v, $w is copy = Whatever, :with(:&as) is copy = WhateverCode, Bool:D :d(:directed-edges(:$directed)) = True) {
         if &as.isa(WhateverCode) { &as = {$_} }
-        my @w;
         given $w {
-            when Whatever { @w = @v }
-            when $_ ~~ (Array:D | List:D | Seq:D) { @w = |$w }
+            when Whatever { $w = @v }
+            when $_ ~~ (Array:D | List:D | Seq:D) {
+                # do nothing
+            }
             default {
                 die 'The third argument is expected to be a list or Whatever.'
             }
         }
-        my @edges = (@v X @w).map({ &f(&as($_.head), &as($_.tail)) ?? Pair.new($_.head.Str, $_.tail.Str) !! Empty });
+        my @edges = (@v X $w.Array).map({ &f(&as($_.head), &as($_.tail)) ?? Pair.new($_.head.Str, $_.tail.Str) !! Empty });
         my Graph $graph = Graph.new(@edges, :$directed);
         return $graph;
     }