code: def call(self, x):
      self.counter.assign_add(1)
      return x
  
imports: import numpy
  import pytest
  from keras import callbacks
  from keras import layers
  from keras import testing
  from keras.models import Sequential
  from keras.utils import file_utils
label_desc: Use image node_id 2 for calling the CanaryLayer obj's underlying member method code with example usage: obj.call(x) and returns: x