quotient CDGA - degree validation

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Hi,

I am trying to compute a minimal model of boundary of triangle, It is known that it can be done via CDGA:

A.<t1,t2,t3,dt1,dt2,dt3> = GradedCommutativeAlgebra(QQ, degrees=[0,0,0,1,1,1])
B = A.cdg_algebra({t1:dt1,t2:dt2,t3:dt3})
I = B.ideal([t1+t2+t3-1,dt1+dt2+dt3,t1*t2*t3,dt1*t2*t3,t1*dt2*t3,t1*t2*dt3,dt1*dt2])
Q = B.quotient(I)
Q.minimal_model(6)

However, it is failing after Evaluation in SageCell on the error:

ValueError: the degree weights must be positive integers

I tried to change order of commands and define quotient after differential but it didn't help.

Thanks for your help!