Python extensible schema validations and declarative syntax helpers.
pip install valley
import valley as v
class Animal(v.Schema):
name = v.StringProperty(required=True)
species = v.StringProperty(required=True)
color = v.StringProperty(required=True)
meal_type = v.StringProperty()
age = v.IntegerProperty(required=True)
frog = Animal(name='Kermit',species='frog',color='green',meal='carnivore',age=1)
frog.validate()