Add Hash Table solution

solutions/object_oriented_design/hash_table/hash_map.py

@@ -0,0 +1,38 @@
+class Item(object):
+
+    def __init__(self, key, value):
+        self.key = key
+        self.value = value
+
+
+class HashTable(object):
+
+    def __init__(self, size):
+        self.size = size
+        self.table = [[] for _ in range(self.size)]
+
+    def _hash_function(self, key):
+        return key % self.size
+
+    def set(self, key, value):
+        hash_index = self._hash_function(key)
+        for item in self.table[hash_index]:
+            if item.key == key:
+                item.value = value
+                return
+        self.table[hash_index].append(Item(key, value))
+
+    def get(self, key):
+        hash_index = self._hash_function(key)
+        for item in self.table[hash_index]:
+            if item.key == key:
+                return item.value
+        raise KeyError('Key not found')
+
+    def remove(self, key):
+        hash_index = self._hash_function(key)
+        for index, item in enumerate(self.table[hash_index]):
+            if item.key == key:
+                del self.table[hash_index][index]
+                return
+        raise KeyError('Key not found')