code: def get_cmd_by_path(self, existed_cmd_path):
          
          parent = self.tree
          for cmd_name in existed_cmd_path:
              try:
                  parent = parent['children'][cmd_name]
              except KeyError:
                  raise ValueError(
                      "Given key [%s] in path %s does not exist in tree."
                      % (cmd_name, existed_cmd_path)
                  )
          return parent
docs: :return:
          {
              "name": cmd_name,
              "cmd": Resource instance,
              "children": {}
          }