如何使用python和pysftp从一个SFTP流式传输到另一个SFTP

import pysftp

source_host = 'source_host'
source_username = 'source_username'
source_password = 'source_password'

source_cnopts = pysftp.CnOpts()
source_cnopts.hostkeys = None

source_sftp = pysftp.Connection(host=source_host, username=source_username, password=source_password, cnopts=source_cnopts)

target_host = 'target_host'
target_username = 'target_username'
target_password = 'target_password'

target_cnopts = pysftp.CnOpts()
target_cnopts.hostkeys = None

target_sftp = pysftp.Connection(host=target_host, username=target_username, password=target_password, cnopts=target_cnopts)

source_file_path = '/path/to/source/file'
target_file_path = '/path/to/target/file'

with source_sftp.open(source_file_path, 'rb') as source_file:
    with target_sftp.open(target_file_path, 'wb') as target_file:
        for chunk in source_file:
            target_file.write(chunk)

source_sftp.close()
target_sftp.close()