new_contents: import pkg_resources
  
  
  def plug_all(group):
      entry_points_group = 'jacquard.%s' % group
  
      for entry_point in pkg_resources.iter_entry_points(entry_points_group):
          yield entry_point.name, entry_point.resolve
  
  
  def plug(group, name=None):
      candidate = None
  
      for point_name, resolver in plug_all(group):
          if point_name != name:
              continue
  
          candidate = resolver
  
      if candidate is None:
          raise RuntimeError("Could not find plugin for '%s'" % name)
  
      return candidate
  
subject: Add basic plugin utility