Use isinstance instead of type comparison when checking token type
Use isinstance instead of type comparison when checking token type

Allow unicode strings.
When using some web frameworks e.g. Django, string values are stored as unicode characters. Using  for comparison fails. Using  would be a better option as it accommodates both  and  types.

Closes expo/exponent-server-sdk-python#5

fbshipit-source-id: 6e44d4f

exponentjs/exponent-server-sdk-python