Executing update by query for a array of arrays


So, one of the metadata I have indexed is a array of arrays. But, I'm having problems when I try to execute a update by query on it. Here is the sintax I'm using:

"source":"ctx._source.Exemple ='[['foobar','10','g/Kg'],['baz','20','g/Kg']]';"

What's wrong, and how do I execute it?

Thank you!