Python extensible schema validations and declarative syntax helpers.
pip install valleyimport 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()