# File lib_core/rucy/process.rb, line 9
    def chenv(name_value_pairs)
      env_var_alist = ENV.to_a
      begin
        ENV.clear
        for name, value in name_value_pairs
          ENV[name] = value
        end
        return yield
      ensure
        ENV.clear
        for name, value in env_var_alist
          ENV[name] = value
        end
      end
    end