Could not find Choice node parent AbsoluteSchemaPath

I get a Error when trying to parse a yang file like below:
choice pool-type {
container interface-pool {
leaf dddd

{ type string; }

list sub-option {
description "Specifieds the user defined DHCP sub options";
key sub-option-code;

leaf sub-option-code {
description "The sub option code of the user defined option";
type uint8

{ range "1..254"; }

}
choice option-format {
leaf-list ip-address

{ description "IP address list"; type string; }

}
}
}
}

the error is:
[ERROR] yang-to-sources: Unable to generate sources with org.opendaylight.yangtools.maven.sal.api.gen.plugin.CodeGeneratorImpl generator
java.lang.IllegalStateException: Could not find Choice node parent AbsoluteSchemaPath

{path=[(com:huawei:controller:application:test?revision=2016-07-12)pool-type, (com:huawei:controller:application:test?revision=2016-07-12)interface-pool, (com:huawei:controller:application:test?revision=2016-07-12)sub-option]}

at com.google.common.base.Preconditions.checkState(Preconditions.java:197)
...

Why compilation of this yang failure?