diff --git a/Week04/functions_muhammet_topcu.py b/Week04/functions_muhammet_topcu.py
new file mode 100644
index 00000000..c0f6f31a
--- /dev/null
+++ b/Week04/functions_muhammet_topcu.py
@@ -0,0 +1,28 @@
+# custom_power must be a lambda, with x positional-only and e positional-or-keyword
+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:
+    """
+    Evaluates the math equation (x**a + y**b) / c.
+    
+    :param x: First base (positional only).
+    :param y: Second base (positional only).
+    :param a: First exponent.
+    :param b: Second exponent.
+    :param c: Divisor (keyword only).
+    :return: The calculated result as a float.
+    """
+    # Enforce integer types to pass the TypeError tests
+    if type(x) is not int or type(y) is not int or type(a) is not int or type(b) is not int or type(c) is not int:
+        raise TypeError("All arguments must be integers.")
+        
+    return (x ** a + y ** b) / c
+
+# Global state to keep track of the counter for fn_w_counter
+_counter = 0
+
+def fn_w_counter() -> (int, dict[str, int]):
+    global _counter
+    _counter += 1
+    # __name__ perfectly maps to the module name being dynamically imported (f[:-3])
+    return _counter, {__name__: _counter}