docs: public final void setAdditionalProperties(final Map<String, String> additionalProperties) {
  
          // no need for validation, the method will create a new (empty) object if the provided parameter is null.
  
          // create a defensive copy of the map and all its properties
          if (additionalProperties == null) {
              // create a new (empty) properties map if the provided parameter was null
              this.additionalProperties = new ConcurrentHashMap<>();
          } else {
              // create a defensive copy of the map and all its properties
              // the code looks a little more complicated than a simple "putAll()", but it catches situations
              // where a Map is provided that supports null values (e.g. a HashMap) vs Map implementations
              // that do not (e.g. ConcurrentHashMap).
              this.additionalProperties = new ConcurrentHashMap<>();
              for (final Map.Entry<String, String> entry : additionalProperties.entrySet()) {
                  final String key = entry.getKey();
                  final String value = entry.getValue();
  
                  if (value != null) {
                      this.additionalProperties.put(key, value);
                  }
              }
          }
      }