code: def test_nopscaler(target, observed):
      s = scaler.NOPScaler()
      target_scaled, scale = s(target, observed)
  
      assert mx.nd.norm(target - target_scaled) == 0
      assert (
          mx.nd.norm(mx.nd.ones_like(target).mean(axis=s.axis) - scale)
          == 0
      )
  
imports: import mxnet
  import numpy
  import pytest
  from gluonts.mx.block import scaler
label_desc: Use image node_id 2 for calling a global function with example usage: test_nopscaler(target, observed) without return types