Create __init__.py

Initialising a LinkedList class, using a Node class to store the item and the next pointer.

data_structures/LinkedList/__init__.py

@@ -0,0 +1,22 @@
+class Node:
+    def __init__(self, item, next):
+        self.item = item
+        self.next = next
+
+class LinkedList:
+    def __init__(self):
+        self.head = None
+
+    def add(self, item):
+        self.head = Node(item, self.head)
+
+    def remove(self):
+        if self.is_empty():
+            return None
+        else:
+            item = self.head.item
+            self.head = self.head.next
+            return item
+
+    def is_empty(self):
+        return self.head == None