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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 _peer_get_bfd(self, tx, rx, multiplier):
 """Get and merge the `bfd` config from global BGP. You should not use this method. You probably want `BGP.bfd`. Args: tx: XML document with the XML to get the transmit interval. rx: XML document with the XML to get the receive interval. multiplier: XML document with the XML to get the interval multiplier. Returns: Merged XML document. Raises: None """

        tx = self._callback(tx, handler='get_config')
        rx = self._callback(rx, handler='get_config')
        multiplier = self._callback(multiplier, handler='get_config')
        tx = pynos.utilities.return_xml(str(tx))
        rx = pynos.utilities.return_xml(str(rx))
        multiplier = pynos.utilities.return_xml(str(multiplier))
        config = pynos.utilities.merge_xml(tx, rx)
        return pynos.utilities.merge_xml(config, multiplier)