Quotient of free algebra on 2 generators (x, y) over rational field by a non-homogenous ideal

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Hi all,

Here I asked a question in sage but there is an error which I can not solve it:

F.<x,y>=FreeAlgebra(QQ)
I=F*[x*y*x*y-y*x, y*x*y*x-x*y]*F
G.<a,b>=F.quo(I)
G

TypeError: quotient() takes exactly 4 arguments (3 given)

Please help me to find the forth argument should I put.

Actually I want to construct a quotient of infinite dimensional non-commutative free algebra F by a non-homogenous ideal.

Thanks