I can't seem to get sketch.import working
Here is the example from the documentation:
```
var sketch = require('sketch/dom')

const svgString =
  '<svg width="200px" height="100px" viewBox="0 0 200 100" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><rect fill="#000000" x="0" y="0" width="200" height="100"></rect></svg>'

const group = sketch.import(svgString, 'svg')
```
I'm running Sketch Beta 54 (76408). I get this error:
```
TypeError: sketch.import is not a function. (In 'sketch.import(svgString, 'svg')', 'sketch.import' is undefined)
line: 7
sourceURL: /Users/kgutowski/Library/Application Support/com.bohemiancoding.sketch3/Plugins/Untitled.sketchplugin
column: 28
stack: onRun@/Users/kgutowski/Library/Application Support/com.bohemiancoding.sketch3/Plugins/Untitled.sketchplugin:7:28
```