code: def childAtPath(self, path):
          
          if self.__root is None:
              return None
          if path[0] == '/':
              path = path[1:]
          path = path.split('/',1)
          if self.getChild(path[0]) is None:
              return None
          if len(path) > 1:
              return self.__root.childAtPath(path[1])
          else:
              return self.__root
docs: Get a child at I{path} where I{path} is a (/) separated
          list of element names that are expected to be children.
          @param path: A (/) separated list of element names.
          @type path: basestring
          @return: The leaf node at the end of I{path}
          @rtype: L{Element}