According to the documentation on Dynamic Keyboards (DynamicKeyboardBase ) the domain field is meant to be READ_WRITE and is meant to be updated when set to a specific string such as "alphanumeric", "generic", "numeric" etc. However, when setting this field, it remains invalid and does not update accordingly.
m.keyboard.domain = "numeric"
This code will print:
Is this a bug with DynamicKeyboardBase?