diff --git a/Week04/functions_ahmet_hakan_yildirim.py b/Week04/functions_ahmet_hakan_yildirim.py
new file mode 100644
index 00000000..42414d9e
--- /dev/null
+++ b/Week04/functions_ahmet_hakan_yildirim.py
@@ -0,0 +1,44 @@
+from typing import Tuple, Dict
+
+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:
+    """
+    :param x: positional-only
+    :param y: positional-only
+    :param a: positional or keyword
+    :param b: positional or keyword
+    :param c: keyword-only
+    :return: result as float
+    """
+
+    values = [x, y, a, b, c]
+
+    for v in values:
+        if not isinstance(v, int):
+            raise TypeError("Arguments must be integers")
+
+    numerator = (x ** a + y ** b)
+    result = numerator / c
+
+    return float(result)
+
+
+def fn_w_counter() -> Tuple[int, Dict[str, int]]:
+    if getattr(fn_w_counter, "count", None) is None:
+        fn_w_counter.count = 0
+
+    fn_w_counter.count += 1
+
+    module_name = __name__.split('.')[-1]
+
+    return fn_w_counter.count, {module_name: fn_w_counter.count}