why is my dictionary not recognized as such

[zatlas1]

I am still a newbie but learning fast. However, Python is still surprising me in strange ways. Here is my code

supported_drivers = {"SQLite" : 1,
                    "Sybase" : 3,
                    "SQLserver" : 7,
                    "Oracle" : 8 ,
                    "MongoDB" : 10,
                    "DynamoDB" : 11
                    }
print (vars(supported_drivers))

and here is the result:
Traceback (most recent call last):
File "Z:\projects\xxx\yyy.py", line 58, in <module>
print (vars(supported_drivers))
TypeError: vars() argument must have __dict__ attribute.

OK, so why is my, seemingly a dictionary, not a dictionary?

Thank you all
ZA