I tried the following example in SAGE
G = DirichletGroup(15) x=G.gens() M=ModularForms(x[0]*x[1]^2,3); S=M.cuspidal_submodule(); f1=S.newforms()[0] f1.atkin_lehner_eigenvalue()
and got an error saying that the subspace was not invariant! The same happened while trying to compute the L-series, and for level 35 for example. Is this a bug?