What is the test for determining whether a defendant can plead guilty to a lesser crime?

Where there is evidence from which a jury could reasonably find the defendant guilty of a lesser offense, the trial court is obliged to give the jury appropriate instructions. (People v. Birks (1998) 19 Cal.4th 108, 117-118.) In determining whether an offense is necessarily included in the charged offense, courts look at the elements of the charged offense, unless the accusatory pleading has alleged facts which would include the lesser crime within the charged offense. (People v. Parson (2008) 44 Cal.4th 332, 349.)