How to use the aiozipkin.sampler.Sampler function in aiozipkin

def test_sample_with_rate():
    sampler = Sampler(sample_rate=0.3, seed=123)
    trace_id = 'bde15168450e7097008c7aab41c27ade'
    assert sampler.is_sampled(trace_id)
    assert sampler.is_sampled(trace_id)
    assert not sampler.is_sampled(trace_id)

def test_sample_never():
    sampler = Sampler(sample_rate=0.0)
    trace_id = 'bde15168450e7097008c7aab41c27ade'
    assert not sampler.is_sampled(trace_id)
    assert not sampler.is_sampled(trace_id)
    assert not sampler.is_sampled(trace_id)

def test_sample_always():
    sampler = Sampler(sample_rate=1.0)
    trace_id = 'bde15168450e7097008c7aab41c27ade'
    assert sampler.is_sampled(trace_id)
    assert sampler.is_sampled(trace_id)
    assert sampler.is_sampled(trace_id)

def create_custom(local_endpoint: Endpoint,
                  transport: Optional[TransportABC] = None,
                  sampler: Optional[SamplerABC] = None) -> Awaitable[Tracer]:
    t = transport or StubTransport()
    sample_rate = 1  # sample everything
    s = sampler or Sampler(sample_rate=sample_rate)

    async def build_tracer() -> Tracer:
        return Tracer(t, s, local_endpoint)

    result: Awaitable[Tracer] = _ContextManager(build_tracer())
    return result

async def build_tracer() -> Tracer:
        sampler = Sampler(sample_rate=sample_rate)
        transport = Transport(
            zipkin_address, send_interval=send_interval, loop=loop)
        return Tracer(transport, sampler, local_endpoint)
    result = _ContextManager(build_tracer())