diff --git a/Week04/functions_buse_demirbas.py b/Week04/functions_buse_demirbas.py
new file mode 100644
index 00000000..e689b67e
--- /dev/null
+++ b/Week04/functions_buse_demirbas.py
@@ -0,0 +1,9 @@
+def custom_power(x , / , e=1)
+    return x**e
+def custom_equation(x=0 , y=0, / , a=1 , b=1, * , c=1) -> float:
+    return (x**a + y**b)/c
+def fn_w_counter():
+    if not hasattr(fn_w_counter, "total_calls"):
+        fn_w_counter.total_calls = 0
+    if not hasattr(fn_w_counter, "callers"):
+        fn_w_counter.callers = {}