App Engine List<String> DB adds chars before string?

I have a field in my db which is a List.

I add strings to that list and it works fine on the development server.

This is the result: [mat12, bg10]

When I do the same on th开发者_运维问答e deploy server, this is the result: [u'mat12', u'bg10']

I don't understand why it adds "u' '" to the string.

I would really appreciate your help.

Thanks

'u' is the Python notation for a unicode string. It's not part of the string: it's outside the quotes.