diff --git a/src/features/call/call_base.R b/src/features/call/call_base.R
index a641b6ee..9c20e81d 100644
--- a/src/features/call/call_base.R
+++ b/src/features/call/call_base.R
@@ -1,5 +1,6 @@
 library('tidyr')
 library('stringr')
+library('entropy')
 
 Mode <- function(v) {
   uniqv <- unique(v)