How do I create an instance of MeshVertices class?

I tried:

foo = bpy.types.MeshVertices()

But it requires an argument “bpy_struct”. I have no idea what it is.

Maybe you should start with this
m = “test_mesh”)
#filling the mesh with something too:??? at once or later?
#??? m.from_pydata(v, e, f )
#??? v,e,f lists of v of 3D-vectors, e and f may be empty [])

and investigate m by e.g. dir(m) or help(m) in the python console?