class_docstr: Accumulator for privacy id count aggregation.
  
  Should be constructed per (privacy_key, privacy_id)
  
  Attributes:
    count: The count of privacy ids in input values.
docstr: Merges the accumulator to self and returns self.
  
  Args:
    accumulator: Another accumulator of the same type to merge.
  
  Returns:
    self
code: def add_accumulator(
      self, accumulator: "PrivacyIdCountAccumulator"
  ) -> "PrivacyIdCountAccumulator":
      """Merges the accumulator to self and returns self.
  
      Args:
        accumulator: Another accumulator of the same type to merge.
  
      Returns:
        self
      """
      self._check_mergeable(accumulator)
      self.count += accumulator.count
      return self
  
imports: import abc
  from typing import Any, List, Sequence
  import pipeline_dp
label_desc: Use image node_id 3 for calling the PrivacyIdCountAccumulator obj's underlying member method code with example usage: obj.add_accumulator(accumulator) and returns: self