This notebook was prepared by Donne Martin. Source and license info is on GitHub.

- Is the input a list of integers?
- Yes

- Can we get negative inputs?
- Yes

- Can there be duplicate entries in the input?
- Yes

- Will there always be at least three integers?
- No

- Can we assume the inputs are valid?
- No, check for None input

- Can we assume this fits memory?
- Yes

- None -> TypeError
- Less than three ints -> ValueError
- [5, -2, 3] -> -30
- [5, -2, 3, 1, -1, 4] -> 60

Refer to the Solution Notebook. If you are stuck and need a hint, the solution notebook's algorithm discussion might be a good place to start.

In [ ]:

```
class Solution(object):
def max_prod_three(self, array):
# TODO: Implement me
pass
```

**The following unit test is expected to fail until you solve the challenge.**

In [ ]:

```
# %load test_prod_three.py
import unittest
class TestProdThree(unittest.TestCase):
def test_prod_three(self):
solution = Solution()
self.assertRaises(TypeError, solution.max_prod_three, None)
self.assertRaises(ValueError, solution.max_prod_three, [1, 2])
self.assertEqual(solution.max_prod_three([5, -2, 3]), -30)
self.assertEqual(solution.max_prod_three([5, -2, 3, 1, -1, 4]), 60)
print('Success: test_prod_three')
def main():
test = TestProdThree()
test.test_prod_three()
if __name__ == '__main__':
main()
```

Review the Solution Notebook for a discussion on algorithms and code solutions.