The python driver considers "$" to be an invalid character in a database name:
https://github.com/mongodb/mongo-python-driver/blob/master/pymongo/database.py#L44

But it should be valid on Linux and Unix systems:
https://docs.mongodb.org/v2.6/reference/limits/#Restrictions-on-Database-Names-for-Unix-and-Linux-Systems

I didn't find any Windows or Linux specific code in pymongo, so maybe pymongo doesn't support any platform specific behavior by design? If that's the case, it'd be nice to get a confirmation.

Additionally, The double quote character should be invalid on all platforms, but passes pymongo's validation.