in src/main/java/aws/cfn/codegen/AttributeType.java [53:60]
public Optional<String> getComplexType() {
// If type is primitive then type == null
if ("List".equals(type) || "Map".equals(type)) {
return Optional.ofNullable(itemType);
}
// Json shows up in type but CFN calls this primitive type. Let us honor it
return Optional.ofNullable("Json".equals(type) ? null : type);
}