Name Error: name 'Stockton' is not defined

[Yoriz]

It does solve the problem of NameError: name 'Stockton' is not defined
what do you want the key names to be represented as?
Note

dictionaries are indexed by keys, which can be any immutable type; strings and numbers can always be keys. Tuples can be used as keys if they contain only strings, numbers, or tuples; if a tuple contains any mutable object either directly or indirectly, it cannot be used as a key. You can’t use lists as keys, since lists can be modified in place using index assignments, slice assignments, or methods like append() and extend().