我认为这解决了您的问题，有关python中位操作的更多信息，请查看此链接->https://realpython.com/python-bitwise-operators/#bit-python中的字符串

def bytes_extraction(bytes, start, length):
    bytes = bin(bytes)
    result = bytes[start:start+length]
    result = int(result, 2)
    return  result

bits = 0b101010 
response = bytes_extraction(bytes=bits , start=2, length=4)
print(response)

下面是一个答案，以您链接的页面为例：

def bytes_extraction(bytes, start, length):

    # Converting a byte to an 8-length binary string
    def format_byte(byte):
        fbyte = bin(byte)[2:]
        fbyte = str(0) * (8 - len(fbyte)) + fbyte
        return fbyte

    # Converting the bytes array into one long bit string
    binstring = "".join([format_byte(byte) for byte in bytes])

    # Converting the bitstring to a base 10 int
    ret_byte = int("0b"+binstring[start:start+length], 2)

    return  ret_byte

example=[ 0b00010101, 0b10101000, 0b00000000, 0b00000000 ]
response = bytes_extraction(example , 7, 11)
print(response)
1696