class Foo(HasProps): col = ColorSpec("colorfield")
class Foo(HasProps): col = ColorSpec("colorfield", default="blue")
class Foo(HasProps): col = ColorSpec("gray")
class Foo(HasProps): col = ColorSpec(default=(128, 255, 124))
class Foo(HasProps): col = ColorSpec(default="red")
class Foo(HasProps): col = ColorSpec("colorfield", default=(128, 255, 124))