old_contents: """
  Runner classes to execute tasks.
  """
  from .simple import *
  
new_contents: """
  Runner classes to execute tasks.
  """
  
  _namemodmap = dict(
      SimpleRunner='simple',
      IPythonParallelRunner='ipython',
  )
  
  
  def getrunner(classname):
      import sys
      module = 'buildlet.runner.{0}'.format(_namemodmap[classname])
      __import__(module)
      return getattr(sys.modules[module], classname)
  
  
  def listrunner():
      return list(_namemodmap)
  
subject: Add buildlet.runner.{getrunner,listrunner}