What is the test for "general principles of law" in a criminal case?

A trial court in a criminal case has a duty to instruct on general principles of law applicable to the case, that is, "'"'those principles closely and openly connected with the facts before the court, and which are necessary for the jury's understanding of the case.'"'" (People v. Valdez (2004) 32 Cal.4th 73, 115.) But "[i]t is error to give an instruction which, while correctly stating a principle of law, has no application to the facts of the case." (People v. Guiton (1993) 4 Cal.4th 1116, 1129.)