Is evidence of precautions taken and repairs made after the accident admissible to prove negligent condition at the time of the accident?

In Helling v. Schindler, 145 Cal. 303, 78 P. 710, 713, it is said: '[I]t is now well settled in this state, in accord with the rule prevailing generally elsewhere, that evidence of precautions take and repairs made after the happening of the accident is not admissible to show a negligent condition at the time of the accident.' These views have been approved in many cases and are based on the sound theory that the fact that a party observes an injury resulting from an accident, and then acts with a view of preventing the possibility of a similar accident again occurring, should operate to commend rather than to condemn the one so acting.