Specify Semantic-UI form theme per class or id

Hello guys, I’ve posted an issue at the semantic-ui github, asking if this feature exists and if it’s documented somewhere. But no one replied yet. So since this is an amazing community and some of you are also working with semantic-ui I wonder if anyone can answer my question. Here it goes:

So I’ve changed the default form theme to be flat, but in some cases it doesn’t fit as good as I wanted.
So what I want to know that I couldn’t find anywhere, is if there is a way to specify a form theme based on a class or id.
Perhaps doing something like:

.ui.github.themed.form {
     @form       : 'github';

But the meaning of that must be “only change the theme for that specific form and not the whole site definition”

For instance:

<form class="ui github themed form"> would render a github based form, that would be the same as @form : 'github' but just for that specific form

And if used normally:

<form class="ui form"> would render the form using the theme defined in the theme.config.import.less variable

Sorry man, but your answer was too vague, did you understand what I’m trying to accomplish? I want to use one of the available form themes [flat, github, chubby, default] for a specific form, without changing the default form theme that I’ve chosen (flat).