X-Git-Url: https://git.njae.me.uk/?a=blobdiff_plain;f=lib%2Fgraph.njae%2Fgraph.rb;h=e08a1ad8544d12aec4cacf3a095ca5e1e5df6aea;hb=5afeed673400a0d1e2c1c0d6b6f286f65723f405;hp=1da5297d1f74861b24ce417dc2ac6c0ff3181111;hpb=c34def40508c16cfc815fa02c8743d071491af7b;p=graph.njae.git

diff --git a/lib/graph.njae/graph.rb b/lib/graph.njae/graph.rb
index 1da5297..e08a1ad 100644
--- a/lib/graph.njae/graph.rb
+++ b/lib/graph.njae/graph.rb
@@ -16,9 +16,9 @@ module GraphNjae
     
     # Add a Vertex or Edge to the graph.
     def <<(other)
-      if other.class == Vertex
+      if other.class.ancestors.include? Vertex
         self.vertices << other
-      elsif
+      elsif other.class.ancestors.include? Edge
         self.edges << other
       end
       self