def match(self, func_ir, block, typemap, calltypes):
        """
        Detect all setitem expressions and find which ones have
        string literal indexes
        """
        self.setitems = setitems = {}
        self.block = block
        self.calltypes = calltypes
        for inst in block.find_insts(ir.SetItem):
            index_ty = typemap[inst.index.name]
            if isinstance(index_ty, types.StringLiteral):
                setitems[inst] = (inst.index, index_ty.literal_value)

        return len(setitems) > 0

        Detect all setitem expressions and find which ones have
        string literal indexes
        
numba/core/rewrites/static_getitem.py