docs: private static List<XsdAttribute> filterAttributes(List<XsdAttribute> attributes) {
          List<String> attributeNames = attributes.stream()
                  .map(XsdNamedElements::getName)
                  .distinct()
                  .collect(Collectors.toList());
  
          List<XsdAttribute> filteredAttributes = new ArrayList<>();
  
          attributeNames.forEach(attributeName -> {
              for (XsdAttribute attribute : attributes) {
                  if (attribute.getName().equals(attributeName)){
                      filteredAttributes.add(attribute);
                      break;
                  }
              }
          });
  
          return filteredAttributes;
      }