diff --git a/Week04/decorators_gokhan_koray_bulbul.py b/Week04/decorators_gokhan_koray_bulbul.py
new file mode 100644
index 00000000..8d069b1d
--- /dev/null
+++ b/Week04/decorators_gokhan_koray_bulbul.py
@@ -0,0 +1,38 @@
+import time
+import tracemalloc
+
+def performance(func):
+    """
+    A decorator that measures execution time and memory usage.
+    Statistics are stored as attributes on the wrapper function.
+    """
+    
+    # Initialize the required attributes on the wrapper function
+    performance.counter = 0
+    performance.total_time = 0.0
+    performance.total_mem = 0
+
+    def _performance(*args, **kwargs):
+
+        # 1. Increment the call counter
+        performance.counter += 1
+        
+        # 2. Start memory tracking
+        tracemalloc.start()
+        
+        # 3. Start timer
+        start_time = time.perf_counter()
+        
+        # Execute the original function
+        result = func(*args, **kwargs)
+        
+        # 4. Stop timer and calculate duration
+        end_time = time.perf_counter()
+        performance.total_time += (end_time - start_time)
+        
+        # 5. Get memory stats (current, peak) and stop tracking
+        _, peak = tracemalloc.get_traced_memory()
+        performance.total_mem += peak
+        tracemalloc.stop()
+    
+    return _performance
diff --git a/Week04/functions_gokhan_koray_bulbul.py b/Week04/functions_gokhan_koray_bulbul.py
new file mode 100644
index 00000000..fba56a3b
--- /dev/null
+++ b/Week04/functions_gokhan_koray_bulbul.py
@@ -0,0 +1,25 @@
+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:
+    """This function returns a float value of the equation (x ** a + y ** b) / c
+
+    :param x: The first term of the equation. Default is 0.
+    :param y: The second term of the equation. Default is 0.
+    :param a: The exponent for the first term of the equation. Default is 1.
+    :param b: The exponent for the second term of the equation. Default is 1.
+    :param c: The divisor for the entire equation. Default is 1.
+    :return: The result of the equation (x ** a + y ** b) / c as a float.
+    """
+    return (custom_power(x, e = a) + custom_power(y, e = b)) / c
+
+def fn_w_counter() -> (int, dict[str, int]):
+    if not hasattr(fn_w_counter, "counter"):
+        fn_w_counter.counter = 0
+        fn_w_counter.callers = {}
+    fn_w_counter.counter += 1
+    caller_name = __name__
+    if caller_name in fn_w_counter.callers:
+        fn_w_counter.callers[caller_name] += 1
+    else:
+        fn_w_counter.callers[caller_name] = 1
+    return fn_w_counter.counter, fn_w_counter.callers
diff --git a/Week05/awaitme_gokhan_koray_bulbul.py b/Week05/awaitme_gokhan_koray_bulbul.py
new file mode 100644
index 00000000..308cb323
--- /dev/null
+++ b/Week05/awaitme_gokhan_koray_bulbul.py
@@ -0,0 +1,10 @@
+import asyncio
+
+def awaitme(givenFunction):
+    if asyncio.iscoroutinefunction(givenFunction):
+        return givenFunction
+
+    async def wrapper(*args, **kwargs):
+        return givenFunction(*args, **kwargs)
+
+    return wrapper
diff --git a/Week06/timer_gokhan_koray_bulbul.py b/Week06/timer_gokhan_koray_bulbul.py
new file mode 100644
index 00000000..a575b932
--- /dev/null
+++ b/Week06/timer_gokhan_koray_bulbul.py
@@ -0,0 +1,14 @@
+import time 
+  
+class Timer: 
+     def __init__(self): 
+         self.start_time = 0.0 
+         self.end_time = 0.0 
+  
+     def __enter__(self): 
+         self.start_time = time.time() 
+         return self 
+  
+     def __exit__(self, a, b, c): 
+         self.end_time = time.time()
+         return True
\ No newline at end of file