Add functions for removing duplicates and counting items

Author: sedat000

Week03/sequences_sedat_celik.py

@@ -0,0 +1,20 @@
+def remove_duplicates(seq: list) -> list:
+    result = []
+    for item in seq:
+        if item not in result:
+            result.append(item)
+    return result
+
+
+def list_counts(seq: list) -> dict:
+    counts = {}
+    for item in seq:
+        counts[item] = counts.get(item, 0) + 1
+    return counts
+
+
+def reverse_dict(d: dict) -> dict:
+    result = {}
+    for key, value in d.items():
+        result[value] = key
+    return result