Traceback (most recent call last):



 "<ipython-input-33-af18c14c7097>", line 1, in <module>

integrate(Sum((-1)**k*x**k, (k,0,oo)).doit(), (x,0,1))



 ".\sympy\integrals\integrals.py", line 1295, in integrate

risch=risch, manual=manual)



 ".\sympy\integrals\integrals.py", line 553, in doit

evalued = Add(*others)._eval_interval(x, a, b)



 ".\sympy\functions\elementary\piecewise.py", line 272, in _eval_interval

int_expr = self._sort_expr_cond(sym, a, b)



 ".\sympy\functions\elementary\piecewise.py", line 343, in _sort_expr_cond

lower, upper = cond.lts, cond.gts
# part 1: initialize with givens

AttributeError: 'And' object has no attribute 'lts'

Traceback (most recent call last):


 ".\test.py", line 24, in <module>

main().main_loop()


 "C:\Program 
s\Python37\lib\site-packages\toga_winforms\app.py", line 49, in main_loop

self._startup()


 "C:\Program 
s\Python37\lib\site-packages\toga_winforms\app.py", line 41, in _startup

self.startup()


 "C:\Program 
s\Python37\lib\site-packages\toga\interface\app.py", line 144, in startup

self.main_window.content = self._startup_method(self)


 ".\test.py", line 9, in build

box = toga.Box()


 "C:\Program 
s\Python37\lib\site-packages\toga_winforms\widgets\box.py", line 10, in __init__

super().__init__(id=id, style=style, children=children)


 "C:\Program 
s\Python37\lib\site-packages\toga\interface\widgets\box.py", line 21, in __init__

super().__init__(id=id, style=style, children=children)


 "C:\Program 
s\Python37\lib\site-packages\toga\interface\widgets\base.py", line 144, in __init__

self.style = CSS()


 "C:\Program 
s\Python37\lib\site-packages\toga\interface\widgets\base.py", line 170, in style

self._style = value.bind(self)
AttributeError: 'CSS' object has no attribute 'bind'
