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

- Is the input number an int?
- Yes

- Can we assume the inputs are valid?
- No

- Is the output a boolean?
- Yes

- Can we assume this fits memory?
- Yes

- None -> TypeError
- 0 -> False
- 1 -> True
- 2 -> True
- 15 -> False
- 16 -> True

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 is_power_of_two(self, val):
# TODO: Implement me
pass
```

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

In [ ]:

```
# %load test_is_power_of_two.py
import unittest
class TestSolution(unittest.TestCase):
def test_is_power_of_two(self):
solution = Solution()
self.assertRaises(TypeError, solution.is_power_of_two, None)
self.assertEqual(solution.is_power_of_two(0), False)
self.assertEqual(solution.is_power_of_two(1), True)
self.assertEqual(solution.is_power_of_two(2), True)
self.assertEqual(solution.is_power_of_two(15), False)
self.assertEqual(solution.is_power_of_two(16), True)
print('Success: test_is_power_of_two')
def main():
test = TestSolution()
test.test_is_power_of_two()
if __name__ == '__main__':
main()
```

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