lib/plugins/platform/platform.js/Platform/getScheduledSubscription
class Platform:  getScheduledSubscription(event, fn) {
    const provider = this.data.service.provider;
    const subscription = {
      functionId: this.serverless.service.getFunction(fn).name,
      type: 'aws.cloudwatch.scheduled',
      details: {
        function: this.serverless.service.getFunction(fn).name,
        source: 'AWS::CloudWatch::Scheduled',
      },
      provider,
      permissions: {
        type: 'aws IAM',
        action: 'lambda:InvokeFunction',
        sourceAccount: 'Amazon',
      },
    };
    if (typeof event === 'string') {
      subscription.details.rate = event;
      subscription.details.name = null;
      subscription.details.description = null;
    } else if (typeof event === 'object') {
      subscription.details.rate = event.rate;
      subscription.details.name = event.name;
      subscription.details.description = event.description;
    }
    subscription.event = event;
    return subscription;
  }