Extracting the normals from a Model at runtime

private static Vector3[] GetNormals(ModelMeshPart meshPart)
{
    if (meshPart.VertexBuffer == null)
        return null;

    VertexBuffer vb = meshPart.VertexBuffer;
    if (meshPart.VertexBuffer.Tag != null) // Vertex buffers can be, and usually are, shared between ModelMeshPart's.
        return (Vector3[]) meshPart.VertexBuffer.Tag;

    VertexDeclaration vd = vb.VertexDeclaration;
    VertexElement[] elements = vd.GetVertexElements();

    Func<VertexElement,bool> normalElementPredicate = ve => ve.VertexElementUsage == VertexElementUsage.Normal && ve.VertexElementFormat == VertexElementFormat.Vector3;
    if (!elements.Any(normalElementPredicate))
        return null;

    VertexElement normalElement = elements.First(normalElementPredicate);

    Vector3[] normals = new Vector3[vb.VertexCount];
    vb.GetData(normalElement.Offset, normals, 0, vb.VertexCount, vd.VertexStride);

    return normals;
}