diff --git a/Week04/functions_niyazi_cetinkaya.py b/Week04/functions_niyazi_cetinkaya.py
new file mode 100644
index 00000000..045a8011
--- /dev/null
+++ b/Week04/functions_niyazi_cetinkaya.py
@@ -0,0 +1,32 @@
+custom_power = lambda x = 0, /, e = 1: x**e
+
+def custom_equation(x: int = 0, y: int = 0, /, a: int = 1, b: int = 1, *, c: int = 1) -> float:
+    """
+    Calculate a custom equation based on the provided parameters.
+
+    The function computes the result of the equation:
+    (x**a + y**b) / c
+
+    :param x: The first integer value (positional-only, default is 0).
+    :param y: The second integer value (positional-only, default is 0).
+    :param a: The exponent for x (positional or keyword, default is 1).
+    :param b: The exponent for y (positional or keyword, default is 1).
+    :param c: The divisor (keyword-only, default is 1).
+    :return: The result of the equation as a float.
+    """
+    return (x**a + y**b) / c
+
+def fn_w_counter() -> (int, dict[str, int]):
+    if not hasattr(fn_w_counter, "call_counter"):
+        fn_w_counter.call_counter = 0
+        fn_w_counter.caller_count_dict = {}
+
+    caller = __name__
+    fn_w_counter.call_counter += 1
+
+    if caller not in fn_w_counter.caller_count_dict:
+        fn_w_counter.caller_count_dict[caller] = 1
+    else:
+        fn_w_counter.caller_count_dict[caller] += 1
+
+    return fn_w_counter.call_counter, fn_w_counter.caller_count_dict