title: Fn::ImportValue does not match type {Array}
body: <p>I faced an issue with using the export and import functionality in CloudFormation. When I tried to import a value which actually is a list (array) I received the following error message "does not match type {Array}".</p>
  
  <p>vpc.yaml (snippet)</p>
  
  <pre><code>PrivateSubnets:
    Description: A list of the private subnets
    Value: !Join [",", [!Ref PrivateSubnetOne, !Ref PrivateSubnetTwo]]
    Export:
      Name: !Join ["-", [!Ref "Environment", "PrivateSubnets"] ]
  </code></pre>
  
  <p>pipeline.yaml (snippet)</p>
  
  <pre><code>Subnets:
    Fn::ImportValue: !Sub "${Environment}-PrivateSubnets"
  </code></pre>
  
  <p>Error message:</p>
  
  <pre><code>    Property validation failure: [Value of property {/VpcConfig/Subnets} does not match type {Array}
  </code></pre>