我的Python为什么会出错

 Traceback (most recent call last):
  File"/cdata/user/0/ru.iiec.pyolroicl 3/files/accomp-files/iie
 e_run/iiec_run.py', line 3 /, in 
    start(fakepyfile,mainpyfile)
  File/clata/user/0/ru.iiec.pyolroicl3/files/accomp-files/iie
 e_run/iiec_run.py , line 30, in start
    execlopen(mainpyfile).reacl(l), --main--.--olict---
  File "zstring, line /b, in 
 NameError: name 'x4' is not lefinedl
 IProgram finishedlj

变量x4没定义

源码可以看看吗name为x4的