property setters in k2.Fsa never get called

[csukuangfj]

See the setter for labels below

k2/k2/python/k2/fsa.py

Lines 440 to 441 in 2537a3f

	@labels.setter
	def labels(self, values) -> None:

Because of the presence of the following function

k2/k2/python/k2/fsa.py

Line 372 in 2537a3f

def __setattr__(self, name: str, value: Any) -> None:

fsa.labels = xxx is always dispatched to fsa.__setattr__, so we can actually remove @labels.setter since it is never called.

---

A minimal example to illustrate the issue is given below

#!/usr/bin/env python3


class Foo:
    @property
    def bar(self):
        return 10

    @bar.setter
    def bar(self, value):
        print("set bar")

    def __setattr__(self, name, value):
        print(f"set attr: {name}")


f = Foo()
print("f.bar", f.bar)
f.bar = 100

The output is

f.bar 10
set attr: bar

[csukuangfj]

Closed via #850