api merge is not working
I tried to merge two maps in [maps.zip](/uploads/7d76b39329b83d640bb461e4b0989243/maps.zip), but generated file does not have content, see below.
`curl 'https://minerva-dev.lcsb.uni.lu/minerva/api/convert/merge/CellDesigner_SBML:CellDesigner_SBML' -i -X POST --data-binary @maps.zip`
```
<?xml version="1.0" encoding="UTF-8"?>
<sbml xmlns="http://www.sbml.org/sbml/level2/version4" xmlns:celldesigner="http://www.sbml.org/2001/ns/celldesigner" level="2" version="4">
<model >
<notes><html xmlns="http://www.w3.org/1999/xhtml"><head><title/></head><body></body></html></notes><annotation>
<celldesigner:extension>
<celldesigner:modelVersion>4.0</celldesigner:modelVersion>
<celldesigner:modelDisplay sizeX="100" sizeY="100"/>
<celldesigner:listOfIncludedSpecies>
</celldesigner:listOfIncludedSpecies>
<celldesigner:listOfCompartmentAliases>
</celldesigner:listOfCompartmentAliases>
<celldesigner:listOfComplexSpeciesAliases>
</celldesigner:listOfComplexSpeciesAliases>
<celldesigner:listOfSpeciesAliases>
</celldesigner:listOfSpeciesAliases>
<celldesigner:listOfProteins></celldesigner:listOfProteins>
<celldesigner:listOfGenes></celldesigner:listOfGenes>
<celldesigner:listOfRNAs></celldesigner:listOfRNAs>
<celldesigner:listOfAntisenseRNAs></celldesigner:listOfAntisenseRNAs>
<celldesigner:listOfLayers></celldesigner:listOfLayers>
</celldesigner:extension>
<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" xmlns:vCard="http://www.w3.org/2001/vcard-rdf/3.0#" xmlns:bqbiol="http://biomodels.net/biology-qualifiers/" xmlns:bqmodel="http://biomodels.net/model-qualifiers/">
<rdf:Description rdf:about="#null">
<dcterms:modified rdf:parseType="Resource"></dcterms:modified>
</rdf:Description>
</rdf:RDF>
</annotation>
<listOfCompartments>
<compartment metaid="default" id="default" name="" size="1" units="volume" >
<notes><html xmlns="http://www.w3.org/1999/xhtml"><head><title/></head><body>
</body></html></notes>
<annotation>
<celldesigner:extension>
</celldesigner:extension>
<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" xmlns:vCard="http://www.w3.org/2001/vcard-rdf/3.0#" xmlns:bqbiol="http://biomodels.net/biology-qualifiers/" xmlns:bqmodel="http://biomodels.net/model-qualifiers/">
<rdf:Description rdf:about="#default">
<dcterms:modified rdf:parseType="Resource"></dcterms:modified>
</rdf:Description>
</rdf:RDF>
</annotation>
</compartment>
</listOfCompartments>
</model></sbml>
issue