diff --git a/participants/scipy_014/pr_tutorial/simple_functions.py b/participants/scipy_014/pr_tutorial/simple_functions.py
index c3dcf8f..af0add5 100644
--- a/participants/scipy_014/pr_tutorial/simple_functions.py
+++ b/participants/scipy_014/pr_tutorial/simple_functions.py
@@ -10,3 +10,9 @@ def factorial(value):
         return 1
     else:
         return value * factorial(value - 1)
+
+def is_prime(value):
+    for i in range(2, value // 2 + 1):
+        if value % i == 0:
+            return False
+    return True