code: @Override
      public void checkMultiNested(final Statement stmt, final Document doc)
              throws SemanticWarning {
          // is the statement nested?
          if (!stmt.hasNestedStatement()) {
              // not nested
              return;
          }
  
          // does it contain more than one nested statement?
          Statement objstmt = stmt.getObject().getStatement();
          if (objstmt.getObject().getStatement() == null) {
              // object term in nested statement
              return;
          }
  
          // Multi-nested statement, prune stmt then throw semantic warning
          pruneStatement(stmt, doc);
  
          // throw semantic warning
          final StringBuilder bldr = new StringBuilder();
          bldr.append("statement nested more than once, " +
                  "pruning statement.");
  
          final String err = SEMANTIC_MULTI_NESTED;
          final String name = bldr.toString();
          throw new SemanticWarning(name, err);
      }
docs: {@inheritDoc}