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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 _setup_qos_extension(self):
 """Setup the QOS extension if it is required."""

        if not CONF.AGENT.enable_qos_extension:
            return
        self._qos_ext = qos_extension.QosAgentExtension()
        self._qos_ext.consume_api(self)
        self._qos_ext.initialize(self._connection, 'hyperv')