code: def find_by_id(self, submission_id):
      
      return self._attacks.get(
          submission_id,
          self._defenses.get(
              submission_id,
              self._targeted_attacks.get(submission_id, None)))
docs: Finds submission by ID.
  
      Args:
        submission_id: ID of the submission
  
      Returns:
        SubmissionDescriptor with information about submission or None if
        submission is not found.