class T::Props::Decorator

def set(instance, prop, value, rules=props[prop.to_sym])
  # For backwards compatibility, fall back to reconstructing the accessor key
  # (though it would probably make more sense to raise in that case).
  instance.instance_variable_set(rules ? rules[:accessor_key] : '@' + prop.to_s, value) # rubocop:disable PrisonGuard/NoLurkyInstanceVariableAccess
end