code: function buildSvgSymbol(size = CONST.DEFAULT_NODE_SIZE, symbolTypeDesc = CONST.SYMBOLS.CIRCLE) {
      return d3Symbol()
          .size(() => size)
          .type(() => _convertTypeToD3Symbol(symbolTypeDesc))();
  }
docs: Build a d3 svg symbol based on passed symbol and symbol type.
  @param  {number} [size=80] - the size of the symbol.
  @param  {string} [symbolTypeDesc='circle'] - the string containing the type of symbol that we want to build
  (should be one of {@link #node-symbol-type|node.symbolType}).
  @returns {Object} concrete instance of d3 symbol.
  @memberof Node/helper