无法访问变量target_urllist

Traceback (most recent call last):
File "C:\smb\AZscanner\web\Aex2\lib\site-packages\flask\app.py", line 2309, in call
return self.wsgi_app(environ, start_response)
File "C:\smb\AZscanner\web\Aex2\lib\site-packages\flask\app.py", line 2295, in wsgi_app
response = self.handle_exception(e)
File "C:\smb\AZscanner\web\Aex2\lib\site-packages\flask\app.py", line 1741, in handle_exception
reraise(exc_type, exc_value, tb)
File "C:\smb\AZscanner\web\Aex2\lib\site-packages\flask\app.py", line 2292, in wsgi_app
response = self.full_dispatch_request()
File "C:\smb\AZscanner\web\Aex2\lib\site-packages\flask\app.py", line 1815, in full_dispatch_request
rv = self.handle_user_exception(e)
File "C:\smb\AZscanner\web\Aex2\lib\site-packages\flask\app.py", line 1718, in handle_user_exception
reraise(exc_type, exc_value, tb)
File "C:\smb\AZscanner\web\Aex2\lib\site-packages\flask\app.py", line 1813, in full_dispatch_request
rv = self.dispatch_request()
File "C:\smb\AZscanner\web\Aex2\lib\site-packages\flask\app.py", line 1799, in dispatch_request
return self.view_functionsrule.endpoint
File "C:\smb\AZscanner\web\web\trace.py", line 41, in trace
return render_template("trace.html", target = target,target_urllist=target_urllist,iplist=iplist,collect_dirs=collect_dirs,collect_ports=collect_ports,subdomain=subdomain)
UnboundLocalError: local variable 'target_urllist' referenced before assignment