I have to write a function recursively to convert a given decimal string ad return a binary. I can't change the first 3 lines of the function(n = Len(a) ... return str(bin(int(a)))) and I don't understand why my solution doesn't work. Does anyone have any suggestions?

{str} -> {str}

def converttobin(a: str) -> str:n = len(a)if n == 1:return str(bin(int(a)))else:return converttobin(str(int(a) % 2)) + str(int(a) % 2)

Instead of sending the remainder, send the quotient str((int)a//2) to the function call.

For decimal to binary conversion, we take remainders as the current output and further apply the conversion on the quotient.