Latex symbols that are operators - how to create SymPy placeholder

{\cal H} in Latex is used for the Hamiltonian in the "1D particle in a box"

https://en.wikipedia.org/wiki/Hamiltonian_(quantum_mechanics)

Needs to be translated to a SymPy operator 

https://docs.sympy.org/latest/modules/physics/quantum/piab.html

The Laplace operator \nabla^2 in Latex is 

delop = Del()

delop.dot(delop())