<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def int_to_bitlist(x: int, pad: int = None) -> Sequence[int]: """Converts an integer to a binary sequence of bits. Pad prepends with sufficient zeros to ensures that the returned list contains at least this number of bits. [0, 1, 0, 0] """

    if pad is None:
        form = '{:0b}'
    else:
        form = '{:0' + str(pad) + 'b}'

    return [int(b) for b in form.format(x)]