PS, while this may seem like a long list, there are only 190 of 565, ~33% of the files matched by the glob that actually require the exception.

OK, as a counterexample E402 triggers on on all the example files where we have references because we call import matplotlib.

Do we

1. not want to have these reference sections?
2. want to move the matplotlib import to the top
3. make E402 an exception for all of examples?

I'd vote for 3, but this PR precludes that.

#############################################################################
#
# ------------
#
# References
# """"""""""
#
# The use of the following functions and methods is shown in this example:

import matplotlib
matplotlib.axes.Axes.inset_axes_from_bounds
matplotlib.axes.Axes.indicate_inset_zoom
matplotlib.axes.Axes.imshow

I am inclined to skip checking E402 everywhere (which will greatly reduce this list).

OK. Done at #11621

Or instead of exceptions, add # noqa on the import. But I don't like these hacks, I'd prefer if we get sphinx-gallery to do this for us.

The problem is that sphinx-gallery has no way to drill down the axes stack for us because of how we've structured it. ping @ImportanceOfBeingErnest @timhoffm @fredrik-1 who seem to understand sphinx-gallery quite well. But the above was the soln we came to. I'm not horribly opposed to #noqa though for this little helper section...

I guess one could in some (yet to be determined way) hack into sphinx gallery and let it produce all examples with #noqa. But it's really odd to have this mysterious (at least to most users looking at matplotlib examples) line in the code.

I would personally vote for skipping the import checks for the examples. Even without the issue of the Reference sections, there are probably enough cases where some import should only occur late in the example. A global ignore for the examples (and tutorials) folder would make the list significantly shorter and prevent having to add an entry for each new example.

I cannot judge if for the rest of the code base it makes sense to ignore E402 completely or on a by-file-basis.