def _validate_child_constexpr_for_compress(self, op: Operation) -> bool:
        """Check if child constexpr ops support current op to be compressed."""
        for child_op in op.outputs[0].child_ops:
            if child_op.op_type.startswith("constexpr_"):
                # Const fed into constexpr_ ops cannot be further compressed.
                return False
        return True
Check if child constexpr ops support current op to be compressed.
coremltools/optimize/coreml/_quantization_passes.py