What is the effect of section 356 of the California Evidence Code on a witness giving evidence?

Evidence Code section 356 provides: "Where part of [a] ... writing is given in evidence by one party, the whole on the same subject may be inquired into by an adverse party; ... and when a detached act, declaration, conversation, or writing is given in evidence, any other act, declaration, conversation, or writing which is necessary to make it understood may also be given in evidence." "The purpose of this section is to prevent the use of selected aspects of a conversation, act, declaration, or writing, so as to create a misleading impression on the subjects addressed." (People v. Arias (1996) 13 Cal.4th 92, 156, 51 Cal.Rptr.2d 770, 913 P.2d 980.)