code: def p_parallelblock_empty(self, p):
          'parallelblock : FORK JOIN'
          p[0] = ParallelBlock((), lineno=p.lineno(1))
          p.set_lineno(0, p.lineno(1)f p_parallelblock_empty(self, p):
          'parallelblock : FORK JOIN'
          p[0] = ParallelBlock((), lineno=p.lineno(1))
          p.set_lineno(0, p.lineno(1))
docs: parallelblock : FORK JOIN