code: def _locate(self, name):
          
          if name == None:
              raise Exception("Dependency name cannot be null")
          if self._references == None:
              raise Exception("References shall be set")
          
          return self._dependencies.get(name)
docs: Gets a dependency locator by its name.
  
          :param name: the name of the dependency to locate.
          :return: the dependency locator or null if locator was not configured.