def load_commits(commit_type, actor_id = nil)
      commits = CommitCollection.new
      if actor_id.nil?
        each { |actor| commits.merge! actor.send(commit_type) }
      elsif key? actor_id
        commits = self[actor_id].send commit_type
      end
      commits
    end
def load_commits(commit_type, actor_id = nil)
      commits = CommitCollection.new
      if actor_id.nil?
        each { |actor| commits.merge! actor.send(commit_type) }
      elsif key? actor_id
        commits = self[actor_id].send commit_type
      end
      commits
    end
Loads the commits authored or committed by all actors in this collection
 or a specific actor

 @param [:authored_commits, :committed_commits] commit_type The type of
        commits to load
 @param [Object] actor_id The ID of the actor, if only the commits of a
        specific actor should be returned
 @return [CommitCollection] All commits authored or committed by the
         actors in this collection or by a specific actor