Partition deepmind directory into two parts

Since I did not pass my one-site interview with DM, but I have been invited to
attempt again, I decided to partition this directory into two parts:
1. part_one: Hosting the exercises that I completed before my first attempt at
   earning the job.
2. part_two: Hosting the exercise that I will complete before my second attempt
   at earning the job.

deepmind/part_two/delete-node.py

@@ -0,0 +1,57 @@
+import unittest
+
+
+def delete_node(node):
+    if node.next:
+        node.value = node.next.value
+        node.next = node.next.next
+    else:
+        raise Exception(
+            "We cannot delete the last node in a linked list using this function"
+        )
+
+
+# Tests
+class Test(unittest.TestCase):
+    class LinkedListNode(object):
+        def __init__(self, value, next=None):
+            self.value = value
+            self.next = next
+
+        def get_values(self):
+            node = self
+            values = []
+            while node is not None:
+                values.append(node.value)
+                node = node.next
+            return values
+
+    def setUp(self):
+        self.fourth = Test.LinkedListNode(4)
+        self.third = Test.LinkedListNode(3, self.fourth)
+        self.second = Test.LinkedListNode(2, self.third)
+        self.first = Test.LinkedListNode(1, self.second)
+
+    def test_node_at_beginning(self):
+        delete_node(self.first)
+        actual = self.first.get_values()
+        expected = [2, 3, 4]
+        self.assertEqual(actual, expected)
+
+    def test_node_in_middle(self):
+        delete_node(self.second)
+        actual = self.first.get_values()
+        expected = [1, 3, 4]
+        self.assertEqual(actual, expected)
+
+    def test_node_at_end(self):
+        with self.assertRaises(Exception):
+            delete_node(self.fourth)
+
+    def test_one_node_in_list(self):
+        unique = Test.LinkedListNode(1)
+        with self.assertRaises(Exception):
+            delete_node(unique)
+
+
+unittest.main(verbosity=2)