def yaml(self):
        return yaml.dump(self.serialized, default_flow_style=False,
                         encoding=None)
def _files(self):
        if self.isexact():
            m1, m2 = self._m1, self._m2
            if not m1.isexact():
                m1, m2 = m2, m1
            return [f for f in m1.files() if m2(f)]
        # It neither m1 nor m2 is an exact matcher, we can't easily intersect
        # the set of files, because their files() are not always files. For
        # example, if intersecting a matcher "-I glob:foo.txt" with matcher of
        # "path:dir2", we don't want to remove "dir2" from the set.
        return self._m1.files() + self._m2.files()