Python-сообщество

rawbytes = bytearray("b", "utf-8")
    for i in command:
        if isinstance(i, int):
            rawbytes.append(i)
        else:
            for j in i:
                rawbytes.append(j)

rawbytes = [(i if isinstance(i, int) else j for j in list(i)) for i in command]

bytearray(flatten(command))

 >>> def flatten(seq):
...     for i in seq:
...         if hasattr(i, '__getitem__'):
...             for j in flatten(i):
...                 yield j
...         else:
...             yield i
... 
>>> lst = [1, 2, 3, [4, 5, [6, 7, [8]]] , 9, 10]
>>> 
>>> bytearray(flatten(lst))            
bytearray(b'\x01\x02\x03\x04\x05\x06\x07\x08\t\n')
>>>