Saving Time-Dependent Solution as File and Loading It

Hello,

Problem:
I am currently solving time-dependent PDEs. The way my code solves the PDEs, it generates a Python list of Functions, which each have 2 components, each at a different time on a MixedElement FunctionSpace. The MixedElement comes from the function having two component functions at each time step and solving several time steps simultaneously in an implicit method. I currently create a reference solution using a very fine mesh to to compare to. I want to store this reference solution list in a file and then load it in other code-runs so I only have to compute it once and save time on future runs. I have looked into several examples involving XDMF files and PVD files, but I can’t get them to work. I was hoping someone could inform me of a way that works in my Fenics version with MixedElements.

Fenics Version:
2019.2.0.dev0