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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def bfloat16_activations_var_getter(getter, *args, **kwargs):
 """A custom getter function for float32 parameters and bfloat16 activations. Args: getter: custom getter *args: arguments **kwargs: keyword arguments Returns: variables with the correct dtype. Raises: KeyError: if "dtype" is not provided as a kwarg. """

  requested_dtype = kwargs["dtype"]
  if requested_dtype == tf.bfloat16:
    kwargs["dtype"] = tf.float32
  var = getter(*args, **kwargs)
  # This if statement is needed to guard the cast, because batch norm
  # assigns directly to the return value of this custom getter. The cast
  # makes the return value not a variable so it cannot be assigned. Batch
  # norm variables are always in fp32 so this if statement is never
  # triggered for them.
  if var.dtype.base_dtype != requested_dtype:
    var = tf.cast(var, requested_dtype)
  return var