internal: Fix caches being orphaned from their directory. After clearing caches, the instances in memory don't have a file-system directory anymore. This means that either caching data would crash the app, or, in the case of baking a site, would make the workers create the directory but collide randomly while doing so at the same time.

PRIORITY_FIRST = -1
PRIORITY_NORMAL = 0
PRIORITY_LAST = 1


class Formatter(object):
    FORMAT_NAMES = None
    OUTPUT_FORMAT = None

    def __init__(self):
        self.priority = PRIORITY_NORMAL

    def initialize(self, app):
        self.app = app

    def render(self, format_name, txt):
        raise NotImplementedError()