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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _key_changed(self, client, cnxn_id, entry, data=None):
 """ Callback when a gconf key changes """

        key = self._fix_key(entry.key)[len(self.GCONF_DIR):]
        value = self._get_value(entry.value, self.DEFAULTS[key])

        self.emit('conf-changed', key, value)