code: def get_forced_variation(self, experiment, user_id):
      
  
      forced_variations = experiment.forcedVariations
      if forced_variations and user_id in forced_variations:
        variation_key = forced_variations.get(user_id)
        variation = self.config.get_variation_from_key(experiment.key, variation_key)
        if variation:
          self.logger.info('User "%s" is forced in variation "%s".' % (user_id, variation_key))
        return variation
  
      return None
docs: Determine if a user is forced into a variation for the given experiment and return that variation.
  
      Args:
        experiment: Object representing the experiment for which user is to be bucketed.
        user_id: ID for the user.
  
      Returns:
        Variation in which the user with ID user_id is forced into. None if no variation.