Utility method to tell kaplan_meier_plot
to combine the given
survival results within the same plot
in_one_kaplan_meier_plot(...)
Internal object for use by kaplan_meier_plot
or
kaplan_meier_grid
only
Named SurvivalAnalysisResult objects as returned by analyse_survival
.
Please note that the results need to come from the same data source and should
only differ by the "by" parameter. The first given result acts as source for common attributes.
Also takes one single named bare list.