implement following the text

Verifying solution...
Test 1 passed!
Test 2 passed!
Test 3 passed! [Hidden]
Test 4 passed! [Hidden]
Test 5 failed  [Hidden]
Test 6 failed  [Hidden]
Test 7 passed! [Hidden]
Test 8 passed! [Hidden]
Test 9 failed  [Hidden]
Test 10 passed! [Hidden]

extra/queue-to-do/solution.py

@@ -0,0 +1,16 @@
+def solution(start, length):
+    checksum = 0
+    for i in range(length):
+        base = start + length * i
+        for j in range(length - i):
+            checksum ^= base + j
+    return checksum
+
+tests = [
+        ([0, 3], 2),
+        ([17, 4], 14)
+        ]
+
+for i, o in tests:
+    result = solution(*i)
+    print (i, result == o, result, o)