old_contents: from twisted.trial import unittest
  
  class TestOperations(unittest.TestCase):
      def testNewOperation(self):
          NS = "pyofwave.info/test"
          E = ElementMaker(namespace=NS)
          # print "tests.py", E.response()
      
          class op(Operation):
              print E.response()
              @staticmethod
              def r(*args, **kwargs):
                  g = globals()
                  print g["NS"], g["op"]
                  ## print "args:", args
                  ## print "kwargs:", kwargs
                  print g["E"], g.keys()
                  return E.response("success", status=400)
  
new_contents: from twisted.trial import unittest
  
  from lxml.builder import ElementMaker
  from pyofwave.core.opdev import Operation
  
  class TestOperations(unittest.TestCase):
      def testNewOperation(self):
          NS = "pyofwave.info/test"
          E = ElementMaker(namespace=NS)
          # print "tests.py", E.response()
      
          class op(Operation):
              print E.response()
              @staticmethod
              def r(*args, **kwargs):
                  g = globals()
                  print g["NS"], g["op"]
                  ## print "args:", args
                  ## print "kwargs:", kwargs
                  print g["E"], g.keys()
                  return E.response("success", status=400)
  
subject: fix missing imports