How to trigger `cf.assert` MLIR operations?

Suppose I have

let _ = __mlir_op.`cf.assert`[msg=__mlir_attr.`"ERROR"`](false)

let _ = __mlir_op.`cf.assert`[msg=__mlir_attr.`"ERROR"`](false)

let _ = __mlir_op.`cf.assert`[msg=__mlir_attr.`"ERROR"`](false)

let _ = __mlir_op.`cf.assert`[msg=__mlir_attr.`"ERROR"`](false)

The error is that it cannot infer the return type of the MLIR operation.

How do I resolve it?

Thank you.