diff --git a/Week04/functions_efesamil_sarigul.py b/Week04/functions_efesamil_sarigul.py
new file mode 100644
index 00000000..a757962b
--- /dev/null
+++ b/Week04/functions_efesamil_sarigul.py
@@ -0,0 +1,34 @@
+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:
+    """
+    Calculates the mathematical equation.
+
+    :param x: The first base value.
+    :type x: int
+    :param y: The second base value.
+    :type y: int
+    :param a: The exponent for x.
+    :type a: int
+    :param b: The exponent for y.
+    :type b: int
+    :param c: The divisor.
+    :type c: int
+    :return: The result of the equation.
+    :rtype: float
+    """
+    return float((x**a + y**b) / c)
+
+def fn_w_counter() -> (int, dict[str, int]):
+    if not hasattr(fn_w_counter, "count"):
+        fn_w_counter.count = 0
+        fn_w_counter.caller_info = {}
+
+    fn_w_counter.count += 1
+
+
+    caller_name = __name__.split('.')[-1]
+    
+    fn_w_counter.caller_info[caller_name] = fn_w_counter.caller_info.get(caller_name, 0) + 1
+
+    return fn_w_counter.count, fn_w_counter.caller_info