code: public VertexElement buildVertexElement(Vertex vertex) {
          if (!tx.isValidElement(vertex)) {
              Objects.requireNonNull(vertex);
              throw TransactionException.invalidElement(vertex);
          }
          return new VertexElement(tx, vertex);
      }
docs: Builds a VertexElement from an already existing Vertex.
  *
  @throws TransactionException if vertex is not valid. A vertex is not valid if it is null or has been deleted
  @param vertex A vertex which can possibly be turned into a VertexElement
  @return A VertexElement of