python3没有不能再使用花括号作为程序段的标记了吗？

import os
from ftplib import FTP
from io import StringIO
import sys
if len(sys.argv) >= 4:
    print("第一个参数：",sys.argv[1])
    print("第二个参数：",sys.argv[2])
    print("第三个参数：",sys.argv[3])
else:
    print("没有提供足够的参数！")
def is_ftp_connection_successful(host, username, password):
    try:
        myFtpObject = FTP(host)
        myFtpObject.login(user = username, passwd = password)
        output = StringIO()
        original_stdout = sys.stdout
        sys.stdout = output
        myFtpObject.dir()
        sys.stdout = original_stdout
        print("FTP连接成功。")
        return True
    except Exception is e:
        print(f"FTP连接失败：{e}")
        return False
    finally:
        if 'myFtpObject' in locals():
            myFtpObject.quit()
host = sys.argv[1]
username = sys.argv[2]
password = sys.argv[3]
if is_ftp_connection_successful(host, username, password):
    print("可以进行后续操作！")
else:
    print("FTP服务器连接失败！")

H:\python\studyPython>python ftpConnTestClass.py 192.168.102.234 stFtpCommUser stFtpComm@User
  File "H:\python\studyPython\ftpConnTestClass.py", line 17
        sys.stdout = output
    ^
TabError: inconsistent use of tabs and spaces in indentation

H:\python\studyPython>python ftpConnTestClass.py 192.168.102.234 stFtpCommUser stFtpComm@User
  File "H:\python\studyPython\ftpConnTestClass.py", line 17
        sys.stdout = output
    ^
TabError: inconsistent use of tabs and spaces in indentation

H:\python\studyPython>python ftpConnTestClass.py 192.168.102.234 stFtpCommUser stFtpComm@User
  File "H:\python\studyPython\ftpConnTestClass.py", line 18
        myFtpObject.dir()
    ^
TabError: inconsistent use of tabs and spaces in indentation

H:\python\studyPython>python ftpConnTestClass.py 192.168.102.234 stFtpCommUser stFtpComm@User
第一个参数： 192.168.55.66
第二个参数： ftpTest
第三个参数： abc
FTP连接成功。
可以进行后续操作！