def lookup(self, fact, cache=True):
if (not cache) or (not self.has_cache()):<EOL><INDENT>val =  self.run_facter(fact)<EOL>if val is None or val == '<STR_LIT>':<EOL><INDENT>raise KeyError(fact)<EOL><DEDENT>return val<EOL><DEDENT>return self._cache[fact]<EOL>
Return the value of a given fact and raise a KeyError if
        it is not available. If `cache` is False, force the lookup of
        the fact.