> I would like code a web service with python.
> ... details omitted ...
Such a task has many facets. Some of them are quite general
and you can find packages on "PyPI" which support them well;
others are highly problem specific and you likely will need
to solve them on your own.
"web service" is an ambigous term: in a wide meaning, it can
be any service provided via HTTP/HTTPS; however, often,
it is used in a narrow way as a SOAP/WSDL service.
There are several packages which help you to implement SOAP services
in Python, among them "spyne" and "soapbox". This gives
you the SOAP aspect (together with WSDL generation).
In addition, you have the "web" aspect. There are other
packages for this: among them "django", "pyramid", "twisted", ...
And there are further more application dependent aspects
like determining the geo location. Look at "PyPI" to find
out whether there are packages that help you with those.
Likely, those will not be pure Python packages but bridges to
other ("C/C++") libraries.