diff --git a/config/runtime.exs b/config/runtime.exs
index 3d4b9be..96b6056 100644
--- a/config/runtime.exs
+++ b/config/runtime.exs
@@ -30,9 +30,15 @@ import Config
 
 config :wabanex, dns_cluster_query: System.get_env("DNS_CLUSTER_QUERY") || :ignore
 
-get_multi_env = fn varnames, default ->
+multi_get_env = fn varnames, default ->
   varnames
-  |> Enum.reduce(nil, &(System.get_env(&1) || &2))
+  |> Enum.reduce(nil, fn
+    varname, nil ->
+      System.get_env(varname) || nil
+
+    _varname, value ->
+      value
+  end)
   |> Kernel.||(default)
 end