Implement LRU cache

Author: RihannaP

Sprint-2/implement_lru_cache/lru_cache.py

@@ -0,0 +1,30 @@
+from collections import OrderedDict
+
+class LruCache:
+
+    def __init__(self, limit):
+        if limit <= 0:
+            raise ValueError("Limit must be positive")
+        
+        self.limit = limit
+        
+        self.cache = OrderedDict()
+
+    def get(self, key):
+
+        if key not in self.cache:
+            return None
+
+        self.cache.move_to_end(key)
+        return self.cache[key]
+
+    def set(self, key, value):
+        
+        if key in self.cache:
+            self.cache.move_to_end(key)
+        
+        self.cache[key] = value
+
+        if len(self.cache) > self.limit:
+
+            self.cache.popitem(last=False)