Tolong jelaskan mengenai Association football dari Nirbobol

In association football and other sports with a goalkeeper, the goalkeeper may be said to "keep a clean sheet" if they prevent their opponents from scoring during an entire match. Because football is a relatively low-scoring game, it is common for one team, or even both teams, to score no goals. A theory as to the term's origin is that sports reporters used separate pieces of paper to record the different statistical details of a game. If one team did not allow a goal, then that team's "details of goals conceded" page would appear blank, leaving a clean sheet. If a game ends with a final score of 0–0, both sides are considered to have kept a clean sheet.