Append an purge model entry to the journal.

        This instructs Revit to purge the open model.

        Args:
            pass_count (int): number of times to execute the purge.
                              default is 3

def purge_unused(self, pass_count=3):
        """Append an purge model entry to the journal.

        This instructs Revit to purge the open model.

        Args:
            pass_count (int): number of times to execute the purge.
                              default is 3
        """
        for purge_count in range(0, pass_count):
            self._add_entry(templates.PROJECT_PURGE)