Problem with pytfa.relax_dgo due to sympy

[embt]

Hello,
first of all big thanks for supporting the package! I had a problem with the function relax_dgo and also a possible solution:
from pytfa.optim.relaxation import relax_dgo
relaxed_model, slack_model, relax_table = relax_dgo(mytfa)

The follwing Error occours:

~\AppData\Roaming\Python\Python38\site-packages\pytfa\optim\utils.py in symbol_sum(variables)
108 k=0
109 # If we encounter a zero, which is a special type, increase k
--> 110 while isinstance(variables[k], sympy.numbers.Zero) and k<len(variables):
111 k+=1
112 if k == len(variables):

AttributeError: module 'sympy' has no attribute 'numbers'

By changing sympy.numbers.Zero to sympy.core.numbers.Zero in ~\AppData\Roaming\Python\Python38\site-packages\pytfa\optim\utils.py the Error is gone.
This seems like sympy changed something there.

I'm using Python Python 3.8.5 and sympy version 1.6.2

Regards,
Emil

[psalvy]

Good day Emil,

Thanks a lot for using our package!
Looks like sympy changed the behavior/location of their Zero object (this suggests maybe it was 14 months ago ?). Thanks for the quick fix you provided! Would you mind sending out a PR for this ?
Cheers,
Pierre

[embt]

I hope I did everything right, I'm a bit new to GitHub.
Thanks!