哪位大佬指点下，是不是写错了，文档里也没查到例子。。。

var test123 = wx.getTextLineHeight({

    'fontFamily':'Arial',

    'text':'你好',

  })

  console.log(test123)

结果报错

VM2497 WAGame.js:2 TypeError: Na is not a function

    at Object.getTextLineHeight (VM2497 WAGame.js:2)

    at Object.C.<computed> (VM2497 WAGame.js:2)

    at Object.<anonymous> (VM2497 WAGame.js:2)