    # File lib/chef/provider/group/usermod.rb, line 32
            def modify_group_members
              case node[:platform]
              when "openbsd", "netbsd", "aix"
                append_flags = "-G"
              when "solaris"
                append_flags = "-a -G"
              end

              unless @new_resource.members.empty?
                if(@new_resource.append)
                  @new_resource.members.each do |member|
                    Chef::Log.debug("#{@new_resource} appending member #{member} to group #{@new_resource.group_name}")
                    run_command(:command => "usermod #{append_flags} #{@new_resource.group_name} #{member}" )

                  end
                else
                  raise Chef::Exceptions::Group, "setting group members directly is not supported by #{self.to_s}"
                end
              else
                Chef::Log.debug("#{@new_resource} not changing group members, the group has no members")
              end
            end