Is a sentence for conspiracy to commit second degree murder invalid under section 1157?

Section 1157. Defendants contend their sentences were invalid under section 1157. That section states, "Whenever a defendant is convicted of a crime or attempt to commit a crime which is distinguished into degrees, the jury, or the court if a jury trial is waived, must find a degree of the crime or attempted crime of which he is guilty. Upon the failure of the jury or the court to so determine, the degree of the crime or attempted crime of which the defendant is guilty, shall be deemed to be of the lesser degree." Section 1157 establishes " 'a rule to which there is to be no exception.' " (People v. McDonald (1984) 37 Cal.3d 351, 382, 208 Cal.Rptr. 236, 690 P.2d 709.) The rule applies whenever the jury fails to specify the degree of the crime on the verdict form. (Ibid.) Defendants argue that because the jury did not specify the degree of the crime they conspired to commit, their crime was deemed under section 1157 to be conspiracy to commit second degree murder.