class A(Model): foo = ListField(Field(type=int, cast=int), cast=lambda x: x.split(',') if isinstance(x, str) else x)
class A(Model): foo = ListField(Field(type=str), validator=validator)
class A(Model): foo = ListField(Field(type=str))
class A(Model): foo = ListField(str, validator=validator)
class A(Model): foo = ListField(str)
class A(Model): foo = ListField(Field(type=int))