# File lib/chef/role.rb, line 132
    def env_run_lists(env_run_lists=nil)
      if (!env_run_lists.nil?)
        unless env_run_lists.key?("_default")
          msg = "_default key is required in env_run_lists.\n"
          msg << "(env_run_lists: #{env_run_lists.inspect})"
          raise Chef::Exceptions::InvalidEnvironmentRunListSpecification, msg
        end
        @env_run_lists.clear
        env_run_lists.each { |k,v| @env_run_lists[k] = Chef::RunList.new(*Array(v))}
      end
      @env_run_lists
    end