Reverse Bits Leetcode Python

Reverse bits of a given the unsigned integer.

For example, given input 43261596 (represented in binary as 00000010100101000001111010011100), return 964176192 ( Represented in binary as 00111001011110000010100101000000).

Followup:
If This function is called many times, what would you optimize it?

Related Problem:reverse Integer

Class solution:    # @param N, an integer    # @return A integer    def reversebits (self, N):        str= ' {0:032b} '. Format (n)        str=str[::-1]        return int (str,2)

Reverse Bits Leetcode Python