yes                                         graphviz_installed?                                                                                                                                                                                                                                          no                                                                                                                                                                                         
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         
                     process all                                                                                                                                                               process only                                                                                                                                sequence                                                                           and                                                                   activity                                                                                     diagrams
                      diagrams