from difflib import context_diff, unified_diff

def bytes_diff(a, b, fromfile=b'', tofile=b'',
                        fromfiledate='', tofiledate='', n=3, lineterm='\n',
                        *, dtype='unified'):
    def decode(s):
        return s.decode('ascii', 'surrogateescape')
    a = list(map(decode, a))
    b = list(map(decode, b))
    fromfile = decode(fromfile)  # could be made conditional
    tofile = decode(tofile)  # ditto

    meth = unified_diff if dtype == 'unified' else context_diff
    for line in meth(a,b,fromfile,tofile, fromfiledate,tofiledate,n,lineterm):
        yield line.encode('ascii', 'surrogateescape')

if __name__ == '__main__':
    a = [b'a', b'b', b'c']
    b = [b'b', b'd', b'c', b'e']

    for line in bytes_diff(a, b): print(line)
    print()
    for line in bytes_diff(a, b, dtype='context'): print(line)

# prints
'''\
b'--- \n'
b'+++ \n'
b'@@ -1,3 +1,4 @@\n'
b'-a'
b' b'
b'+d'
b' c'
b'+e'

b'*** \n'
b'--- \n'
b'***************\n'
b'*** 1,3 ****\n'
b'- a'
b'  b'
b'  c'
b'--- 1,4 ----\n'
b'  b'
b'+ d'
b'  c'
b'+ e'
'''