Warning: is_writeable is deprecated. Use Folks.PersonaStore.is_primary_store.
Whether the PersonaStore is writeable.
If this property is
false, it doesn't mean that Personas in this
persona store aren't writeable at all. If their properties are updated through the
Persona, rather than through the Individual containing that persona, changes may
be propagated to the backing store.
PersonaStores must not set this property themselves; it will be set as appropriate by the IndividualAggregator.