path = 'C://path/to/my/files'
cnopts = pysftp.CnOpts()
cnopts.hostkeys = None
with pysftp.Connection('111.222.333.444', username='username', password='password', cnopts=cnopts) as sftp:

    sftp.put(path + 'file1.txt' , preserve_mtime=True)
    time.sleep(5)
    sftp.put(path + 'file2.txt' , preserve_mtime=True)
    time.sleep(5)
    sftp.put(path + 'file3.txt' , preserve_mtime=True)
    time.sleep(5)

    sftp.close()