Program to find the 1's complement of a binary number

check_binary.py

# Program to find the 1's complement of a binary number
def check_binary(num):
    """Returns true if the number is binary else, False"""
    for i in str(num):
        if i not in ('0', '1'): return False
    return True


def find_one_complement(num):
    """Returns one's complement of the number"""
    num_str = ''
    for i in str(num): num_str += '1' if i == '0' else '0'
    return num_str


# Take integer input
try:
    number = int(input("Enter the number to check: "))
except ValueError:
    print("Please enter a positive integer: ")
    number = int(input("Enter the number to check: "))

if __name__ == "__main__":
    # Check if the number is binary, and calculate its one's complement if so
    if check_binary(number): print("1's complement of ", number, " is ", find_one_complement(number))
    else: print(number, " is not a binary number")