new_contents: from sklearn.utils.metaestimators import make_delegation_decorator
  from nose.tools import assert_true
  
  
  class Prefix(object):
      def func():
          pass
  
  
  class MockMetaEstimator(object):
      """This is a mock meta estimator"""
      a_prefix = Prefix()
  
      @make_delegation_decorator("a_prefix")
      def func(self):
          """This is a mock delegated function"""
          pass
  
  
  def test_delegated_docstring():
      assert_true("This is a mock delegated function"
                  in str(MockMetaEstimator.__dict__['func'].__doc__))
      assert_true("This is a mock delegated function"
                  in str(MockMetaEstimator().func.__doc__))
  
subject: add regression test for docstring delegation