safe-state.update doesn't work with unnamed function #1

#let a = state("state", 5)
#a.update(n => n + 5)
#context assert.eq(a.get(), 10)

#import "@preview/typsy:0.2.0"
#let a = typsy.safe-state(() => {}, 5)
#(a.update)(n => n + 5)
#context assert.eq((a.get)(), 10) // Failed assertion.