module RuboCop::Cop::Util

def on_node(syms, sexp, excludes = [], &block)
  return to_enum(:on_node, syms, sexp, excludes) unless block_given?
  yield sexp if Array(syms).include?(sexp.type)
  return if Array(excludes).include?(sexp.type)
  sexp.each_child_node { |elem| on_node(syms, elem, excludes, &block) }
end