'Set the hatching pattern
*hatch* can be one of::
/   - diagonal hatching
\   - back diagonal
|   - vertical
-   - horizontal
+   - crossed
x   - crossed diagonal
o   - small circle
O   - large circle
.   - dots
*   - stars
Letters can be combined, in which case all the specified
hatchings are done.  If same letter repeats, it increases the
density of hatching of that pattern.
Hatching is supported in the PostScript, PDF, SVG and Agg
backends only.
ACCEPTS: [\'/\' | \'\\\' | \'|\' | \'-\' | \'+\' | \'x\' | \'o\' | \'O\' | \'.\' | \'*\']'

def set_hatch(self, hatch):

    self._hatch = hatch
    self.stale = True
