code: @SuppressWarnings("PMD")
      public void add(final Statement... toAdd) {
  
          if (toAdd != null) {
  
              Arrays.stream(toAdd)
                      .filter(Objects::nonNull)
                      .forEach(c -> {
  
                          // Resolve the type of the current Statement, and assign it to
                          // the appropriate internal state.
                          if (c instanceof CommonEdgeAttributes) {
                              this.commonEdgeAttributes = (CommonEdgeAttributes) c;
                          } else if (c instanceof CommonGraphAttributes) {
                              this.commonGraphAttributes = (CommonGraphAttributes) c;
                          } else if (c instanceof CommonNodeAttributes) {
                              this.commonNodeAttributes = (CommonNodeAttributes) c;
                          } else if (c instanceof Node) {
                              this.nodes.add((Node) c);
                          } else if (c instanceof Identifier) {
                              this.identifiers.add((Identifier) c);
                          } else if (c instanceof Edge) {
                              this.edges.add((Edge) c);
                          } else if (c instanceof Subgraph) {
                              this.subgraphs.add((Subgraph) c);
                          }
                      });
          }
      }
docs: Adds one or more {@link Statement} objects to this {@link Statements} holder.
  
  @param toAdd One or more {@link Statement} instances.