How to access nx, ny, nz fields

[SyZbidi]

Hi,
I've been trying to convert the x, y, z, nx, ny, nz fields of a ply file from double to float. I managed to do that to x,y,z but I didn't know how to retrieve the normals nx, ny, nz.
Any suggestion on how to do that? 🙏
Thank you in advance,

#!/usr/bin/env python3

import meshio
import numpy as np

mesh_path = "/workspace/object_reconstruction_ws/src/blade.ply"  # double
mesh = meshio.read(mesh_path)

mesh.points[:] = mesh.points.astype(np.float32)
# convert nx,ny,nz ?
mesh.write("mesh-float.ply")