diff --git a/fib.py b/fib.py
index 50722c2..5b4963c 100644
--- a/fib.py
+++ b/fib.py
@@ -6,11 +6,12 @@
 Negative numbers should return None
 """
 def fibonacci(position):
+  if (position < 0):
+    return None
   if(position == 1 or position == 2):
     return 1
   return fibonacci(position - 1) + fibonacci(position - 2)
 
-
 # Test cases
 print("The 1st Fibonacci number: ", fibonacci(1))
 print("The 21st Fibonacci number: ", fibonacci(21))