def tobin(deci_num, len=32):
    """
    Given a decimal number, returns a string bitfield of length = len
    Example: given deci_num = 1 and len = 10, it return 0000000001
    """
    bitstr = "".join(map(lambda y: str((deci_num >> y) & 1), range(len - 1, -1, -1)))
    return bitstr
Given a decimal number, returns a string bitfield of length = len
    Example: given deci_num = 1 and len = 10, it return 0000000001