Traceback (most recent call last):


 "<stdin>", line 1, in <module>


 "./sympy/core/basic.py", line 915, in subs

rv = rv._subs(old, new, **kwargs)


 "./sympy/core/basic.py", line 1029, in _subs

rv = fallback(self, old, new)


 "./sympy/core/basic.py", line 1006, in fallback

rv = self.func(*args)


 "./sympy/tensor/indexed.py", line 157, in __new__

return base[args]


 "./sympy/sets/fancysets.py", line 923, in __getitem__

rv = (self.stop if i < 0 else self.start) + i*self.step
TypeError: unorderable types: list() < int()

Traceback (most recent call last):


 "/home/username/programs/anaconda3/lib/python3.7/site-packages/kivy/core/window/window_sdl2.py", line 747, in mainloop

self._mainloop()


 "/home/username/programs/anaconda3/lib/python3.7/site-packages/kivy/core/window/window_sdl2.py", line 479, in _mainloop

EventLoop.idle()


 "/home/username/programs/anaconda3/lib/python3.7/site-packages/kivy/base.py", line 345, in idle

Builder.sync()


 "/home/username/programs/anaconda3/lib/python3.7/site-packages/kivy/lang/builder.py", line 788, in sync

call_fn(next_args[:-1], None, None)
TypeError: 'NoneType' object is not subscriptable
