'Flush a given job group
Return True if the group had any elements.'

def _group_flush(self, group, name):

    njobs = len(group)
    if njobs:
        plural = {1: ''}.setdefault(njobs, 's')
        print ('Flushing    %s    %s    job%s.' % (njobs, name, plural))
        group[:] = []
        return True
