old_contents: import sys
  import unittest
  
  from nose2 import main, loader, runner, session
  __unittest = True
  
  
  def collector():
      class Test(unittest.TestCase):
          def run(self, result_):
              ok = self._collector(result_)
              sys.exit(not ok)
  
          def _collector(self, result_):
              ssn = session.Session()
              ldr = loader.PluggableTestLoader(ssn)
              rnr = runner.PluggableTestRunner(ssn)
  
              ssn.loadConfigFiles('unittest.cfg', 'nose2.cfg', 'setup.cfg')
              ssn.prepareSysPath()
              ssn.loadPlugins(main.PluggableTestProgram.defaultPlugins)
  
              test = ldr.loadTestsFromNames([], None)
              rslt = rnr.run(test)
              return rslt.wasSuccessful()
  
      return Test('_collector')
  
new_contents: import sys
  import unittest
  
  from nose2 import loader, runner, session
  from nose2.main import PluggableTestProgram
  __unittest = True
  
  
  def collector():
      class Test(unittest.TestCase):
          def run(self, result_):
              ok = self._collector(result_)
              sys.exit(not ok)
  
          def _collector(self, result_):
              ssn = session.Session()
              ldr = loader.PluggableTestLoader(ssn)
              rnr = runner.PluggableTestRunner(ssn)
  
              ssn.loadConfigFiles('unittest.cfg', 'nose2.cfg', 'setup.cfg')
              ssn.prepareSysPath()
              ssn.loadPlugins(PluggableTestProgram.defaultPlugins)
  
              test = ldr.loadTestsFromNames([], None)
              rslt = rnr.run(test)
              return rslt.wasSuccessful()
  
      return Test('_collector')
  
subject: Fix broken import in collector.py.