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

- Are we working with non-negative ints?
- Yes

- What is the range of the integers?
- Discuss the approach for 4 billion integers
- Implement for 32 integers

- Can we assume the inputs are valid?
- No

- None -> Exception
- [] -> Exception
- General case
- There is an int excluded from the input -> int
- There isn't an int excluded from the input -> None

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 [ ]:

```
from bitstring import BitArray # run pip install bitstring
class Bits(object):
def new_int(self, array, max_size):
# TODO: Implement me
pass
```

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

In [ ]:

```
# %load test_new_int.py
import unittest
class TestBits(unittest.TestCase):
def test_new_int(self):
bits = Bits()
max_size = 32
self.assertRaises(TypeError, bits.new_int, None, max_size)
self.assertRaises(TypeError, bits.new_int, [], max_size)
data = [item for item in range(30)]
data.append(31)
self.assertEqual(bits.new_int(data, max_size), 30)
data = [item for item in range(32)]
self.assertEqual(bits.new_int(data, max_size), None)
print('Success: test_find_int_excluded_from_input')
def main():
test = TestBits()
test.test_new_int()
if __name__ == '__main__':
main()
```

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