class Metanorma::Generic::Converter

def empty_metadata_cleanup(ext)

Process elements in reverse doc order to handle nested removals properly
Keep cleaning until no more elements are removed (recursive depth-first) 
def empty_metadata_cleanup(ext)
  loop do
    removed_count = 0
    ext.xpath(".//*").reverse_each do |element|
      element.children.empty? && element.attributes.empty? or next
      element.remove
      removed_count += 1
    end
    removed_count.zero? and break # Stop when no elems removed this pass
  end
end