For the purposes of this Code, where a court is dealing with an offender for an offence, a mandatory sentence requirement applies in relation to the offence if—
the offence is one for which the sentence is fixed by law,
the court is obliged by one of the following provisions to pass a sentence of detention for life, custody for life or imprisonment for life—
section 258, 258A, 274, 274A, 285 or 285A (life sentence for certain ... offenders);
section 273 or 283 (life sentence for second listed offence),
the court is obliged by section 268B or 282B to impose a serious terrorism sentence, or
a sentence is required by one of the following provisions and the court is not of the opinion mentioned in that provision—
section 311(2) (minimum sentence for certain offences involving firearms that are prohibited weapons);
section 312(2) or (2A) (minimum sentence for offence of threatening with weapon or bladed article);
section 313(2) or (2A) (minimum sentence of 7 years for third class A drug trafficking offence);
section 314(2) or (2A) (minimum sentence of 3 years for third domestic burglary);
section 315(2) or (2A) (minimum sentence for repeat offence involving weapon or corrosive substance or bladed article).