diff --git a/fib.py b/fib.py
index 421cfab..e17b5c4 100644
--- a/fib.py
+++ b/fib.py
@@ -6,9 +6,14 @@
 Negative numbers should return None
 """
 def fibonacci(position):
-  if(position == 1 or position == 2):
+  if position < 0:
+    return None
+  elif position == 0:
+     return 0
+  elif position == 1:
     return 1
-  return fibonacci(position - 1) + fibonacci(position - 2)
+   else:
+    return fibonacci(position - 1) + fibonacci(position - 2)