diff --git a/Week03/sequences_serhat_tufan.py b/Week03/sequences_serhat_tufan.py
new file mode 100644
index 00000000..51fd8428
--- /dev/null
+++ b/Week03/sequences_serhat_tufan.py
@@ -0,0 +1,36 @@
+def remove_dublicates(list_:list) ->list:
+    mini_cache= set()
+    will_returned=[]
+    if(list_ ==[]):
+        return []
+    for i in range(len(list_)):
+        if(list_[i] in mini_cache):
+            pass
+        else:
+            mini_cache.add(list_[i])
+            will_returned.append(list_[i])
+    return will_returned
+
+def list_counts(list_:list) ->dict:
+    mini_cache= dict()
+    if(list_ ==[]):
+        return {}
+    for i in range(len(list_)):
+        if(list_[i] in mini_cache):
+            mini_cache[list_[i]] += 1
+        else:
+            mini_cache[list_[i]] = 1
+            
+    return mini_cache
+
+def reverse_dict(dict_:dict) ->dict:
+    mini_cache= dict() 
+    for key, value in dict_.items():
+        mini_cache[value] = key
+        
+    return mini_cache
+    
+
+print(remove_dublicates([1, 2, 3, 3, 4, 5, 5, 5, 6]))
+print(list_counts([1,1,1,1,1,1]))
+print(reverse_dict({1: 1, 2: 1, 3: 1}))