From b70460915d91a3ecae39e6ee17707d7d29792de4 Mon Sep 17 00:00:00 2001
From: "Mr.Perfect 092" <135037455+stephan-maina@users.noreply.github.com>
Date: Fri, 1 Sep 2023 22:50:42 +0300
Subject: [PATCH] Update functions.py

---
 lib/functions.py | 28 ++++++++++++++++++++++------
 1 file changed, 22 insertions(+), 6 deletions(-)

diff --git a/lib/functions.py b/lib/functions.py
index 9d84754d7..ad9c55ae6 100644
--- a/lib/functions.py
+++ b/lib/functions.py
@@ -1,16 +1,32 @@
-#!/usr/bin/env python3
+# lib/functions.py
 
 def greet_programmer():
-    pass
+    print("Hello, programmer!")
 
 def greet(name):
-    pass
+    print("Hello, {}!".format(name))
 
 def greet_with_default(name="programmer"):
-    pass
+    print("Hello, {}!".format(name))
 
 def add(num1, num2):
-    pass
+    return num1 + num2
 
 def halve(number):
-    pass
+    if not isinstance(number, (int, float)):
+        return None
+    
+    return number / 2
+
+# Testing the methods
+if __name__ == "__main__":
+    greet_programmer()
+    greet("Stephan Maina")
+    greet_with_default("Bat-Tziyon Mbiki")
+    greet_with_default()
+    result = add(10, 5)
+    print("The sum is:", result)
+    halved_value = halve(20)
+    print("Half of 20 is:", halved_value)
+    invalid_result = halve("two")
+    print("Invalid result:", invalid_result)