problem: couldn't parse this bundle

Hi, there :-)

Due to some reasons, I can not leak my js file out for this issue. :worried:

Maybe you can give me a little advice about this.

I encounter this error at command line: `couldn't parse this bundle`, and after that, clone this repo, do debug to find where throw this error, finally, I find [this line](https://github.com/substack/browser-unpack/blob/master/index.js#L21), it will return when ast.body.length not equal 1, but here is my ast.body(see the picture below)


There are `"ExpressionStatement"`, `"IfStatement"` there. Because I know nothing about ast things, but maybe you can give me a advice how to fix this? Thanks in advance.