Case sensitive ric codes

Hello,

We're working with a few ric codes that appears to mix small and capital letters. When we request this information, the api responds with a TSIUnknownInstrument-error.

For example, Titan Cement Company SA has the ric code TTNr.AT. This information is found through the search tool https://developers.thomsonreuters.com/elektron/elektron-sdk-java/dev-tools?type=ric

I noticed that you translate the ric codes to upper case in the time_series.py

if is_string_type(rics):
        rics = [rics.strip().upper()]

This is possibly an error. Could you confirm this?