code: def _mk_imp_override(srcname, replacement):
      
      class DummyImporter(object):
          def find_module(self, fullname, path):
              if fullname == srcname:
                  return self
  
              return None
  
          def load_module(self, fullname):
              if fullname != srcname:
                  raise ImportError
              sys.modules[fullname] = replacement
              return replacement
  
      obj = DummyImporter()
      sys.meta_path.append(obj)
docs: Create a simple one for one replacement for a module
      :param srcname: The source module name to replace
      :param replacement: The object which should act as the replacement