How to change the input in RLE to bytes in Python 3?

Question

I'm trying to change the RLE compress algorithm in python 3. I want the input to be bytes instead of string. The code works with string but it does not compress bytes.

Here is the code:

def encode(data) -> bytes:
    encoding = ''
    prev_byte = ''
   
    count = 1
    if not data: return ''

    for bytes in data:
        
        if bytes != prev_byte:
           
            if prev_byte:
                encoding += str(count) + prev_byte
            count = 1
            prev_byte = bytes
        else:
           
            count += 1
    else:
        encoding += str(count) + prev_byte
        return encoding

encoded = encode('AAAABBBCC')
print(encoded)

The Output is: 4A3B2C I need the input AAAABBBCC in bytes and also the output in bytes.