---
AWSTemplateFormatVersion: "2010-09-09"
Description: >
  Exclusive Property types
Conditions:
  isRegion: !If [!Ref 'AWS::Region', 'us-east-1']
  isNotRegion: !Not isRegion
Resources:
  myInstance:
    Type: AWS::EC2::Instance
    Properties:
      ImageId: ami-123456
      SubnetId: subnet-123456
      NetworkInterfaces:
      -
        DeviceIndex: String