diff --git a/src/main/scala/net/virtualvoid/sbt/graph/DependencyGraphSettings.scala b/src/main/scala/net/virtualvoid/sbt/graph/DependencyGraphSettings.scala
index 2bf7a13b6..15b443775 100644
--- a/src/main/scala/net/virtualvoid/sbt/graph/DependencyGraphSettings.scala
+++ b/src/main/scala/net/virtualvoid/sbt/graph/DependencyGraphSettings.scala
@@ -142,7 +142,7 @@ object DependencyGraphSettings {
   def printFromGraph(f: ModuleGraph ⇒ String) =
     Def.task { streams.value.log.info(f(moduleGraph.value)) }
 
-  def showLicenseInfo(graph: ModuleGraph, streams: TaskStreams) {
+  def showLicenseInfo(graph: ModuleGraph, streams: TaskStreams): Unit = {
     val output =
       graph.nodes.filter(_.isUsed).groupBy(_.license).toSeq.sortBy(_._1).map {
         case (license, modules) ⇒
diff --git a/src/main/scala/net/virtualvoid/sbt/graph/rendering/GraphML.scala b/src/main/scala/net/virtualvoid/sbt/graph/rendering/GraphML.scala
index 436a90c2e..e1681fdad 100644
--- a/src/main/scala/net/virtualvoid/sbt/graph/rendering/GraphML.scala
+++ b/src/main/scala/net/virtualvoid/sbt/graph/rendering/GraphML.scala
@@ -21,7 +21,7 @@ import net.virtualvoid.sbt.graph.ModuleGraph
 import scala.xml.XML
 
 object GraphML {
-  def saveAsGraphML(graph: ModuleGraph, outputFile: String) {
+  def saveAsGraphML(graph: ModuleGraph, outputFile: String): Unit = {
     val nodesXml =
       for (n ← graph.nodes)
         yield <node id={ n.id.idString }><data key="d0">