B3 headers value not passed as str

[phonghpham]

We've instrumented our service with LightStep and OpenTracing but have run into a snag when using B3 propagation.

    opentracing.tracer = lightstep.Tracer(
        component_name=c.SERVICE_NAME,
        access_token=OPEN_TRACE_ACCESS_TOKEN,
        tags=tags
    )
    opentracing.tracer.register_propagator(Format.TEXT_MAP, B3Propagator())
    opentracing.tracer.register_propagator(
        Format.HTTP_HEADERS, B3Propagator()
    )

this is the error I'm seeing in developer satellite:

error
     message:
     "Value for header {x-b3-sampled: 1} must be of type str or bytes, not <class 'int'>"
     error.object:
     "Value for header {x-b3-sampled: 1} must be of type str or bytes, not <class 'int'>"
     error.kind:
     "InvalidHeader"

stack trace:

"line 51, in get response = requests.get( File "/usr/local/lib/python3.8/site-packages/requests/api.py", line 75, in get return request('get', url, params=params, **kwargs) File "/usr/local/lib/python3.8/site-packages/requests/api.py", line 60, in request return session.request(method=method, url=url, **kwargs) File "/usr/local/lib/python3.8/site-packages/requests/sessions.py", line 519, in request prep = self.prepare_request(req) File "/usr/local/lib/python3.8/site-packages/requests/sessions.py", line 452, in prepare_request p.prepare( File "/usr/local/lib/python3.8/site-packages/requests/models.py", line 314, in prepare self.prepare_headers(headers) File "/usr/local/lib/python3.8/site-packages/requests/models.py", line 448, in prepare_headers check_header_validity(header) File "/usr/local/lib/python3.8/site-packages/requests/utils.py", line 944, in check_header_validity raise InvalidHeader("Value for header {%s: %s} must be of type str or " "

Appears to be failing python requests library's header validation