I am trying to do some numerics with new forms for $\Gamma_0(N)$. E.g
sage: g=CuspForms(group=Gamma0(2),weight=26).newforms(names='a')[0].q_expansion(prec=10).truncate()
sage: g(exp(-10.))
gives me (an approximation) of the chosen newform at $10i\in \mathbb H$. The chosen newform has coefficients in $\mathbb Q$
If instead I choose another new form
sage: g=CuspForms(group=Gamma0(2),weight=26).newforms(names='a')[1].q_expansion(prec=10).truncate()here
which has coefficients in the number field with defining polynomial $x^2 - 767888x - 9686519804864$ the command
sage:g(-10.)
gives me an error which I interpret as Sage not knowing where to compute or that I have not fixed an embedding of the number field.
How do I fix an embedding and compute g(-10.)
?