How to use the pproxy.ciphers.AES256CFBCipher function in pproxy

class DESCFBCipher(BaseCipher):
    KEY_LENGTH = 8
    IV_LENGTH = 8
    def setup(self):
        self.cipher = DES.new(self.key, DES.MODE_CFB, iv=self.iv, segment_size=64)

MAPPINGS = {\
    'table': TableCipher,
    'rc4': RC4Cipher,
    'rc4-md5': RC4MD5Cipher,
    'chacha20': ChaCha20Cipher,
    'salsa20': Salsa20Cipher,
    'aes-128-cfb': AES128CFBCipher,
    'aes-192-cfb': AES192CFBCipher,
    'aes-256-cfb': AES256CFBCipher,
    'bf-cfb': BFCFBCipher,
    'cast5-cfb': CAST5CFBCipher,
    'des-cfb': DESCFBCipher,
}

def get_cipher(cipher_key):
    cipher, _, key = cipher_key.partition(':')
    cipher, ota, _ = cipher.partition('!')
    if not key:
        raise argparse.ArgumentTypeError('empty key')
    if cipher not in MAPPINGS:
        raise argparse.ArgumentTypeError(f'existing ciphers: {list(MAPPINGS.keys())}')
    cipher, key, ota = MAPPINGS[cipher], key.encode(), bool(ota) if ota else False
    def apply_cipher(reader, writer):
        reader_cipher, writer_cipher = cipher(key, ota=ota), cipher(key, ota=ota)
        def feed_data(s, o=reader.feed_data):

def setup(self):
        self.cipher = ChaCha20.new(key=self.key, nonce=self.iv)

class Salsa20Cipher(BaseCipher):
    KEY_LENGTH = 32
    IV_LENGTH = 8
    def setup(self):
        self.cipher = Salsa20.new(key=self.key, nonce=self.iv)

class AES256CFBCipher(BaseCipher):
    KEY_LENGTH = 32
    IV_LENGTH = 16
    def setup(self):
        self.cipher = AES.new(self.key, AES.MODE_CFB, iv=self.iv, segment_size=128)

class AES128CFBCipher(AES256CFBCipher):
    KEY_LENGTH = 16

class AES192CFBCipher(AES256CFBCipher):
    KEY_LENGTH = 24

class BFCFBCipher(BaseCipher):
    KEY_LENGTH = 16
    IV_LENGTH = 8
    def setup(self):
        self.cipher = Blowfish.new(self.key, Blowfish.MODE_CFB, iv=self.iv, segment_size=64)

class CAST5CFBCipher(BaseCipher):
    KEY_LENGTH = 16
    IV_LENGTH = 8
    def setup(self):
        self.cipher = CAST.new(self.key, CAST.MODE_CFB, iv=self.iv, segment_size=64)

class Salsa20Cipher(BaseCipher):
    KEY_LENGTH = 32
    IV_LENGTH = 8
    def setup(self):
        self.cipher = Salsa20.new(key=self.key, nonce=self.iv)

class AES256CFBCipher(BaseCipher):
    KEY_LENGTH = 32
    IV_LENGTH = 16
    def setup(self):
        self.cipher = AES.new(self.key, AES.MODE_CFB, iv=self.iv, segment_size=128)

class AES128CFBCipher(AES256CFBCipher):
    KEY_LENGTH = 16

class AES192CFBCipher(AES256CFBCipher):
    KEY_LENGTH = 24

class BFCFBCipher(BaseCipher):
    KEY_LENGTH = 16
    IV_LENGTH = 8
    def setup(self):
        self.cipher = Blowfish.new(self.key, Blowfish.MODE_CFB, iv=self.iv, segment_size=64)

class CAST5CFBCipher(BaseCipher):
    KEY_LENGTH = 16
    IV_LENGTH = 8
    def setup(self):
        self.cipher = CAST.new(self.key, CAST.MODE_CFB, iv=self.iv, segment_size=64)

class DESCFBCipher(BaseCipher):
    KEY_LENGTH = 8