Small grammatical mistake in Preface

[ritog]

In the Section titled "Why Julia" in the Preface, I noticed a small grammatical mistake.

In the last paragraph, it is written that-

It is the responsibility of the programmer to optimize the code that forms a bottleneck, but this can done in Julia itself.

Focus is on- [...] this can done in Julia itself..

I think a be is missing here. And the corrected sentence fragment would be-

**[...] this can be done in Julia itself. **

Making the whole sentence-

It is the responsibility of the programmer to optimize the code that forms a bottleneck, but this can be done in Julia itself.