human
I found an interesting problem on https://leetcode.com/problems/power-of-four/:
Given an integer (signed 32 bits), write a function to check whether it is a power of 4.

Example:
Given num = 16, return true.
Given num = 5, return false.

Follow up: Could you solve it without loops/recursion?

Credits:Special thanks to @yukuairoy  for adding this problem and creating all test cases.

I tried it in Python, but could not do it. Can you solve it?

 ... Write me a the Python code you requested?
assistant
#Here is the Python code you requested.

class Solution:
     def isPowerOfFour(self, num):
         """
         :type num: int
         :rtype: bool
         """
         return num != 0 and num & (num -1) == 0 and num & 0x55555555 == num