There is XML data passed in POST request as a simple string and not inside some name=value pair,
with HTTP header (optionally) set to 'Content-Type: text/xml'.
How can I get this data in Python (by its own ways or by tools of Django)?
I'm not quite sure what you're asking. Do you just want to know how to access the POST data? You can get that via request.body, which will contain your XML as a string. You can then use your favourite Python XML parser on it.
request.body also in Flask. Perhaps, some kind of a standard.