def unmarshal(self, v):
        if self.units:
            # Note that we don't want to cast to type in this case!
            if not isinstance(v, Quantity):
                v = self.units(v)
        elif not isinstance(v, self.type):
            v = self.type(v)
        return v
Returns whether this query is keys only.
dataset/ETHPy150Open hozn/stravalib/stravalib/attributes.py/Attribute.unmarshal--crossover with--dataset/ETHPy150Open AppScale/appscale/AppServer/google/appengine/ext/db/__init__.py/_BaseQuery.is_keys_only