code: static void parseFilter(final ModelNode operation, final XMLExtendedStreamReader reader) throws XMLStreamException {
          final StringBuilder filter = new StringBuilder();
          parseFilterChildren(filter, false, reader);
          operation.get(FILTER_SPEC.getName()).set(filter.toString());
      }
docs: A helper to parse the deprecated {@code filter} for schema versions {@code 1.0} and {@code 1.1}. This parses the
  XML and creates a {@code filter-spec} expression. The expression is set as the value for the {@code filter-spec}
  attribute on the operation.
  
  @param operation the operation to add the parsed filter to
  @param reader    the reader used to read the filter
  
  @throws XMLStreamException if a parsing error occurs