code: public void setStatements(List<AstNode> statements) {
          if (this.statements != null) {
              this.statements.clear();
          }
          for (AstNode s : statements) {
              addStatement(s);
          }
      }
docs: Sets statement list.  May be {@code null}.  Replaces any existing
  statements.  Each element in the list has its parent set to this node.