Mesh code can no longer access FV relation

[albertoferna]

I have a piece of code that use to work in previous versions of Taichi. I just did a new clean install (it installed 1.7.0 using pip). I have tried to isolate as much as posible the example:

mesh = Patcher.load_mesh(mesh_file, relations=["VV", "FV", "FE", "EV", "VF"])
@ti.kernel
def checks() -> int:
    i = 0
    for f in mesh.faces:
        face = f
        for v in f.verts:
            i += 1
    return i
checks()

As far as I understand that code should work, however I get:

build_nested_mesh_for  entry_expr = _ti_core.get_relation_access(
TypeError: get_relation_access(): incompatible function arguments. The following argument types are supported:
    1. (arg0: taichi::lang::mesh::MeshPtr, arg1: taichi._lib.core.taichi_python.Expr, arg2: taichi::lang::mesh::MeshElementType, arg3: taichi._lib.core.taichi_python.Expr, arg4: taichi._lib.core.taichi_python.DebugInfo) -> taichi._lib.core.taichi_python.Expr

Invoked with: <taichi._lib.core.taichi_python.MeshPtr object at 0x000001A3766D41F0>, <taichi._lib.core.taichi_python.Expr object at 0x000001A37C19AA30>, <MeshElementType.Vertex: 0>, <taichi._lib.core.taichi_python.Expr object at 0x000001A37C13B8B0>

Anybody can point me into what I'm doing wrong? All I need is to loop each of the vertex of a face to get some properties out of them.
Thank you for your time