private List<Step> readSteps(Element stepTag, Map<String, String> prodAttributes, Element parentTag, Bcp defaultBcp) {
        if (stepTag.getTagName().equals(instanceTag))
            return new ArrayList<>(readInstanceContent(stepTag.getAttribute(idAttribute), stepTag, prodAttributes, parentTag, defaultBcp));
        else
            return readNonInstanceSteps(stepTag, prodAttributes, parentTag, defaultBcp);

    }
Reads the content of an (implicit or explicit) instance tag producing an instances step

@param instanceNameString a comma-separated list of the names of the instances this is for
@param instanceElement the element having the content of this instance
@param parentTag the parent of instanceTag (or the same, if this instance is implicitly defined, which means instanceTag is the root)
@return the instances specified, one for each instance name element
config-model-api/src/main/java/com/yahoo/config/application/api/xml/DeploymentSpecXmlReader.java