# File lib/chef/provider/group/pw.rb, line 73
        def set_members_option
          opt = ""
          unless @new_resource.members.empty?
            opt << " -M #{@new_resource.members.join(',')}"
            Chef::Log.debug("#{@new_resource} setting group members to #{@new_resource.members.join(', ')}")
          else
            # New member list is empty so we should delete any old group members
            unless @current_resource.members.empty?
              opt << " -d #{@current_resource.members.join(',')}"
              Chef::Log.debug("#{@new_resource} removing group members #{@current_resource.members.join(', ')}")
            else
              Chef::Log.debug("#{@new_resource} not changing group members, the group has no members")
            end
          end
          opt
        end