Using UltiSnips, I'd like to add a set of snippets just for one file or for a set of files in the same directory, maybe using a `:vim` modeline. 

I tried to put 

```
 let g:UltiSnipsSnippetDirectories=["UltiSnips", "."]

```

in my `.vimrc` and then adding a `all.snippets` file in the same directory of the file (by the way, it is a LaTeX file — I tried also with `tex_local.snippets` file) but it doesn't work. 

The rational is the following: I am writing a `beamer` presentation and I have a repeating pattern for several frames --- one that is two diagrams side by side for example, another a figure and a plot, and so on. 

So I have defined snippets that create the 3 or 4 patterns I like for this presentation, and happily added them to my `.vimtex/UltiSnips/tex_local.snippets` file --- and all is fine. But these snippets are really only useful for *this* file, and at the end of the day I do not want to keep adding very local things to the generic snippets definitions...