from opentelemetry import trace
from opentelemetry.context import Context
from opentelemetry.sdk.trace import Tracer

trace.set_preferred_tracer_implementation(lambda T: Tracer())
tracer = trace.tracer()
with tracer.start_span('foo'):
    print(Context)
    with tracer.start_span('bar'):
        print(Context)
        with tracer.start_span('baz'):
            print(Context)
        print(Context)
    print(Context)