It's not a problem if 1st instance is already halfway done when the second just starts, their local variables are not related to each other.

如果第一个实例已经完成一半了，第二刚开始那就不是个问题，他们的局部变量互不相关。

youdao

If the two sides can't agree, everyone's taxes will rise sharply on January 1st, dealing a body-blow to the feeble economy.

如果双方不能达成一致，那么到明年1月1日，每个人都要面临大幅的增税，将给疲弱的经济造成严重挫折。

youdao

If we had a national holiday, it would be April 1st.

如果要为全国黑客选一个假日，那一定是愚人节。

youdao

We can ensure that taxes on 98 percent of the American people do not go up on January 1st if the House simply passes a bill that's passed the Senate.

WHITEHOUSE: Press Briefing by Press Secretary Jay Carney,

On January 1st, if nothing is done, everybody here is going to get a tax hike.

WHITEHOUSE: President Obama on Retaining Teachers and the American Jobs Act | The White House

Interest rates on those loans will double overnight, starting on July 1st, if Congress does not act.

WHITEHOUSE: President Obama Speaks on Student Loan Interest Rates in Colorado | The White House