def enumerate_params_by_node(node)
      attrs = enumerate_attrs_by_node(node)
      Set.new(attrs.select { |a| @param_set.include?(a) })
    end
def enumerate_params_by_node(node)
      attrs = enumerate_attrs_by_node(node)
      Set.new(attrs.select { |a| @param_set.include?(a) })
    end
enumerate params by a single node