code: def test_call(self):
      buf = []
  
      def setter(env, agent, value):
          buf.append(value)
  
      hook = pfrl.experiments.LinearInterpolationHook(
          total_steps=10, start_value=0.1, stop_value=1.0, setter=setter
      )
  
      for step in range(1, 10 + 1):
          hook(env=None, agent=None, step=step)
  
      np.testing.assert_allclose(
          buf, np.arange(1, 10 + 1, dtype=np.float32) / 10
      )
  
imports: import unittest
  import numpy
  import pfrl
label_desc: Use image node_id 1 for calling the TestLinearInterpolationHook obj's underlying member method code with example usage: obj.test_call() without return types