code: def add(
      self,
      action: types.NestedArray,
      next_timestep: dm_env.TimeStep,
      extras: types.NestedArray = (),
  ):
      del action
      del extras
      self.counts[int(next_timestep.observation[0])] += 1
  
file_path: acme/acme/agents/jax/lfd/lfd_adder_test.py
imports: import collections
  from acme import adders
  from acme import types
  from acme.agents.jax.lfd import lfd_adder
  import dm_env
  import numpy
  from absl.testing import absltest
label_desc: Use image node_id 4 for calling the TestStatisticsAdder obj's underlying member method code with example usage: obj.add(action, next_timestep, extras) without return types