def save(self, f: Union[str, BinaryIO]):
        """
        Save the mesh to a .npz file.
        """
        if isinstance(f, str):
            with bf.BlobFile(f, "wb") as writer:
                self.save(writer)
        else:
            obj_dict = dict(verts=self.verts, faces=self.faces)
            if self.normals is not None:
                obj_dict["normals"] = self.normals
            for k, v in self.vertex_channels.items():
                obj_dict[f"v_{k}"] = v
            for k, v in self.face_channels.items():
                obj_dict[f"f_{k}"] = v
            np.savez(f, **obj_dict)

        Save the mesh to a .npz file.
        
shap_e/rendering/mesh.py