# rational weights of (affine) Lie algebra

I am studying affine Lie algebra with non-integral level and weights.

However, multiplying a rational number, like -3/4, to the affine fundamental weights will cause an error `TypeError: unsupported operand parent(s) for *: 'Rational Field' and 'Extended weight lattice of the Root system of type ['A', 2, 1]'`

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**I wonder how to work with rationals?**