この Ipython をテストすることはできませんが、「警告をサポートするために warn=False を設定できます」と Ipython は教えてくれます。
ソース:
matplotlib.use?
Type: function
String Form:<function use at 0x98da02c>
File: /usr/lib/pymodules/python2.7/matplotlib/__init__.py
Definition: matplotlib.use(arg, warn=True)
Docstring:
Set the matplotlib backend to one of the known backends.
The argument is case-insensitive. For the Cairo backend,
the argument can have an extension to indicate the type of
output. Example:
use('cairo.pdf')
will specify a default of pdf output generated by Cairo.
.. note::
This function must be called *before* importing pyplot for
the first time; or, if you are not using pyplot, it must be called
before importing matplotlib.backends. If warn is True, a warning
is issued if you try and call this after pylab or pyplot have been
loaded. In certain black magic use cases, e.g.
:func:`pyplot.switch_backends`, we are doing the reloading necessary to
make the backend switch work (in some cases, e.g. pure image
backends) so one can set warn=False to supporess the warnings.
To find out which backend is currently set, see
:func:`matplotlib.get_backend`.
ドキュメントのタイプミスを見つけるのはいつも楽しいです。