<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def fuzzer(buffer, fuzz_factor=101):
 """Fuzz given buffer. Take a buffer of bytes, create a copy, and replace some bytes with random values. Number of bytes to modify depends on fuzz_factor. This code is taken from Charlie Miller's fuzzer code. :param buffer: the data to fuzz. :type buffer: byte array :param fuzz_factor: degree of fuzzing. :type fuzz_factor: int :return: fuzzed buffer. :rtype: byte array """

    buf = deepcopy(buffer)
    num_writes = number_of_bytes_to_modify(len(buf), fuzz_factor)
    for _ in range(num_writes):
        random_byte = random.randrange(256)
        random_position = random.randrange(len(buf))
        buf[random_position] = random_byte
    return buf