Add a task from vObject to Taskwarrior
        vtodo -- the iCalendar to add
        project -- the project to add (see get_filesnames() as well)

def append_vobject(self, vtodo, project=None):
        """Add a task from vObject to Taskwarrior
        vtodo -- the iCalendar to add
        project -- the project to add (see get_filesnames() as well)
        """
        if project:
            project = basename(project)
        return self.to_task(vtodo.vtodo, project)