def count_binary_ones(number):
    """
    Returns the number of 1s in the binary representation of number (>=0)
    For e.g 5 returns 2 (101 has 2 1's), 21 returns 3 ("10101")
    """
    # Use only builtins to get this done. No control statements plz
    return bin(number)[2:].count("1")