code: def ref_epsilon_insensitive_loss_forward(x0, x1, epsilon):
      y = np.zeros_like(x0)
      abs_diff = np.abs(x0 - x1)
      idx = np.where(abs_diff > epsilon)
      y[idx] = abs_diff[idx] - epsilon
      return y
  
imports: import pytest
  import numpy
  import nnabla.functions
  from nbla_test_utils import list_context
label_desc: Use image node_id 1 for calling a global function with example usage: ref_epsilon_insensitive_loss_forward(x0, x1, epsilon) and returns: y