code: def build(self, variables):
      if self.use_ema:
          self._model_variables_moving_average = []
      if self.gradient_accumulation_steps:
          self._accumulated_gradients = []
      for i, variable in enumerate(variables):
          self._trainable_variables_indices[self._var_key(variable)] = i
          if self.use_ema:
              self._model_variables_moving_average.append(
                  self.add_variable_from_reference(
                      variable,
                      name="average",
                  )
              )
          if self.gradient_accumulation_steps:
              self._accumulated_gradients.append(
                  self.add_variable_from_reference(
                      variable,
                      name="gradient_accumulator",
                  )
              )
      self._trainable_variables = variables[:]
      self.built = True
  
imports: import re
  import warnings
  import numpy
  from keras import backend
  from keras import initializers
  from keras import ops
  from keras.optimizers.schedules import learning_rate_schedule
  from keras.saving import serialization_lib
  from keras.utils import tracking
  from keras.utils.naming import auto_name
label_desc: Use image node_id 3 for calling the BaseOptimizer obj's underlying member method code with example usage: obj.build(variables) without return types