新生研讨课Python作业（思考题是在b站看视频学会的）

txt = '''I am happy to join with you today in what will go down in history as the greatest demonstration for freedom in the history of our nation.
Five score years ago, a great American, in whose symbolic shadow we stand today, signed the Emancipation Proclamation. This momentous decree came as a great beacon light of hope to millions of Negro slaves who had been seared in the flames of withering injustice. It came as a joyous daybreak to end the long night of bad captivit

新生研讨课Python作业（思考题是在b站看视频学会的）最先出现在Python成神之路。