California Code
CHAPTER 7 - General Rules of Pleading
Section 457.

457. In pleading the performance of conditions precedent in a contract, it is not necessary to state the facts showing such performance, but it may be stated generally that the party duly performed all the conditions on his part, and if such allegation be controverted, the party pleading must establish, on the trial, the facts showing such performance.

(Enacted 1872.)