diff --git a/lib/gexf/document.rb b/lib/gexf/document.rb
index 14fe3dd..e2bd294 100644
--- a/lib/gexf/document.rb
+++ b/lib/gexf/document.rb
@@ -72,7 +72,7 @@ def dispatch_event(tagname, attributes)
 
    def sanitize_attrs(attributes)
      Hash[*attributes.flatten].
-       symbolize_keys.
+       symbolize_keys_for_gexf.
        symbolize_graph_types
    end
 
diff --git a/lib/gexf/support.rb b/lib/gexf/support.rb
index 0fedc75..01063b0 100644
--- a/lib/gexf/support.rb
+++ b/lib/gexf/support.rb
@@ -4,7 +4,7 @@
                      GEXF::Graph::MODES).uniq
 
 class Hash
-  def symbolize_keys
+  def symbolize_keys_for_gexf
     hash = {}
     each { |k,v| hash[k.to_sym] = delete(k) }
     merge(hash)