diff --git a/Week04/functions_elif_ozkanat.py b/Week04/functions_elif_ozkanat.py
new file mode 100644
index 00000000..73256d91
--- /dev/null
+++ b/Week04/functions_elif_ozkanat.py
@@ -0,0 +1,32 @@
+# custom_power (lambda)
+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: integer value
+    :param y: integer value
+    :param a: integer value
+    :param b: integer value
+    :param c: integer value
+    :return: result of equation
+    """
+    if not all(isinstance(v, int) for v in (x, y, a, b, c)):
+        raise TypeError("All parameters must be int")
+
+    return (x ** a + y ** b) / c
+
+
+_call_count = 0
+
+def fn_w_counter() -> (int, dict[str, int]):
+    global _call_count
+    _call_count += 1
+    return _call_count, {__name__: _call_count}