docs: def participate(self, identity, experiment_name, variant):
          """
          Set the variant for a specific user and mark a participation for the
          experiment.
  
          Participation will *only* be marked for visitors who have been verified
          as humans (to avoid skewing reports with requests from bots and web
          crawlers).
          """
          self.set_variant(identity, experiment_name, variant)
          if self.is_verified_human(identity):
              self.mark_participant(experiment_name, variant)