public static ValidationOverrides fromXml(Reader reader) {
        try {
            return fromXml(IOUtils.readAll(reader));
        } catch (IOException e) {
            throw new IllegalArgumentException("Could not read validation-overrides", e);
        }
    }
Returns a ValidationOverrides instance with the content of the given Reader.

@param reader the reader containing a validation-overrides XML structure
@return a ValidationOverrides from the argument
@throws IllegalArgumentException if the validation-allows.xml file exists but is invalid
config-model-api/src/main/java/com/yahoo/config/application/api/ValidationOverrides.java