def add_highlight(self, artist, *args, **kwargs):
hl = _pick_info.make_highlight(<EOL>artist, *args,<EOL>**ChainMap({"<STR_LIT>": self.highlight_kwargs}, kwargs))<EOL>if hl:<EOL><INDENT>artist.axes.add_artist(hl)<EOL>return hl<EOL><DEDENT>
Create, add, and return a highlighting artist.

This method is should be called with an "unpacked" `Selection`,
possibly with some fields set to None.

It is up to the caller to register the artist with the proper
`Selection` (by calling ``sel.extras.append`` on the result of this
method) in order to ensure cleanup upon deselection.