(x, y, xi)
Error in lines 1-1
Traceback (most recent call last):
File "/cocalc/lib/python2.7/site-packages/smc_sagews/sage_server.py", line 995, in execute
exec compile(block+'\n', '', 'single') in namespace, locals
File "", line 1, in <module>
NameError: name 'xi' is not defined