code: def _concat(fun1, fun2):
      """Concatenation of two converter functions, using the same store.
  
      Parameters
      ----------
      fun1, fun2 : functions in converter signature, see datatypes._convert
  
      Returns
      -------
      function in converter signature, see datatypes._convert
          concatenation fun2 o fun1, using the same store
      """
  
      def concat_fun(obj, store=None):
          obj1 = fun1(obj, store=store)
          obj2 = fun2(obj1, store=store)
          return obj2
  
      return concat_fun
  
label_desc: Use image node_id 1 for calling a global function with example usage: _concat(fun1, fun2) and returns: concat_fun, obj2