def subscribing_to_optional_target?(optional_target_name, subscribe_as_default = ActivityNotification.config.subscribe_as_default)
      optional_target_key = Subscription.to_optional_target_key(optional_target_name)
      subscribe_as_default ?
        !optional_targets.has_key?(optional_target_key) || optional_targets[optional_target_key] :
         optional_targets.has_key?(optional_target_key) && optional_targets[optional_target_key]
    end
def subscribing_to_optional_target?(optional_target_name, subscribe_as_default = ActivityNotification.config.subscribe_as_default)
      optional_target_key = Subscription.to_optional_target_key(optional_target_name)
      subscribe_as_default ?
        !optional_targets.has_key?(optional_target_key) || optional_targets[optional_target_key] :
         optional_targets.has_key?(optional_target_key) && optional_targets[optional_target_key]
    end
Returns if the target subscribes to the specified optional target.

 @param [Symbol]  optional_target_name Symbol class name of the optional target implementation (e.g. :amazon_sns, :slack)
 @param [Boolean] subscribe_as_default Default subscription value to use when the subscription record does not configured
 @return [Boolean] If the target subscribes to the specified optional target