diff --git a/operators/ltnp_operator.cr b/operators/ltnp_operator.cr
index de3d826..88cada8 100644
--- a/operators/ltnp_operator.cr
+++ b/operators/ltnp_operator.cr
@@ -3,7 +3,7 @@ require "../records/ltnp_record"
 
 class LtnpOperator
   def initialize(ltnp_data = "")
-    if ltnp_data.nil?
+    if ltnp_data.empty?
       ltnp_data = CommandRunner.run_ltnp
     end
     records = ltnp_data.each_line