How can one find an integral basis of $\mathbb{Q}$-vector space of cuspidal holomorphic modular forms of level $\Gamma_0(p)$ and weight $2$ that have Fourier coefficients in $\mathbb{Q}$? Suchs forms are automatically newforms (because there are no holomorphic modular forms of level $1$ and weight $2$).
I am able to find a basis for the space of all cuspidal holomorphic modular forms of level $\Gamma_0(p)$ and weight $2$ (including those that have non-rational Fourier coefficients) using Newforms(Gamma0(p), 2, names="a") but I do not see how to get what I need from that.
