class Foo(HasProps):
x = NumberSpec("xfield")
class Foo(HasProps):
y = NumberSpec(default=12)
class Mixin(HasProps):
mixin_num = NumberSpec(14)
class Sub(Base, Mixin):
sub_num = NumberSpec(16)
class Base(HasProps):
num = NumberSpec(12)
not_a_dataspec = Float(10)