Define Latex packages in reST file

Hello,

We used |Docutils| to produce reST document, and then make a TeX file
via |rst2latex|.

In the |rst| file, we have added a lot of LaTeX code like:

|.. raw:: latex ~\\ \rule{\textwidth}{1pt} ~\\ |

But I do not know where to add packages like |\usepackage{tabulary}|.

If I add it in the |rst| file like I've shown above, even in the very
beginning, this |\usepackage| line is automatically added
after |\begin{document}| in the tex output file. This obviously
generates an error.

Any idea where can I add |\usepackage| commands in reST?

Thanks

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