def threshold(self, n=None):
        """
        Returns the threshold number of tasks that need to be complete in order to consider the
        workflow as being complete itself. This takes into account the
        :py:attr:`law.BaseWorkflow.acceptance` parameter of the workflow. The threshold is passed
        to the :py:class:`law.TargetCollection` (or :py:class:`law.SiblingFileCollection`) within
        :py:meth:`output`. By default, the maximum number of tasks is taken from the length of the
        branch map. For performance purposes, you can set this value, *n*, directly.
        """
        if n is None:
            n = len(self.task.branch_map())

        acceptance = self.task.acceptance
        return (acceptance * n) if acceptance <= 1 else acceptance