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I want to compute the expectation value of the energy $\langle H \rangle$ for a quantum system with the wave function $\psi(x)$. This is done with $$\langle H \rangle = \int_{-\infty}^{\infty} \psi^* \hat{H} \psi d x$$ where $$\hat{H} = - \frac{\hbar^2}{2 m} \frac{d^2}{d x^2} + V(x)$$ is the Hamiltonian operator for some potential $V(x)$. How do I express $\frac{d}{d x}$ in sage if I don't know on which function it will be applied?

I know it is possible to use psi.diff(x), but is there a way to declare the operator so that it automatically does the derivative when it is multiplied with some function?