def disable_hidden_api_blacklist(self):
        """If necessary and possible, disables hidden api blacklist."""
        version_codename = self._ad.adb.getprop('ro.build.version.codename')
        sdk_version = int(self._ad.adb.getprop('ro.build.version.sdk'))
        # we check version_codename in addition to sdk_version because P builds
        # in development report sdk_version 27, but still enforce the blacklist.
        if self._ad.is_rootable and (sdk_version >= 28
                                     or version_codename == 'P'):
            self._ad.adb.shell(
                'settings put global hidden_api_blacklist_exemptions "*"')
If necessary and possible, disables hidden api blacklist.