'By default, we expect obj to be a screen and split
it on whitespace.
Note that this does not change the case.
In some applications you may want to lowecase everthing
so that "king" and "King" generate the same token.
Override this in your subclass for objects other
than text.
Alternatively, you can pass in a tokenizer as part of
instance creation.'

def getTokens(self, obj):

    return self._tokenizer.tokenize(obj)
