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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 remove_port_channel(self, **kwargs):
 """ Remove a port channel interface. Args: port_int (str):
 port-channel number (1, 2, 3, etc). callback (function):
 A function executed upon completion of the method. The only parameter passed to `callback` will be the ``ElementTree`` `config`. Returns: Return value of `callback`. Raises: KeyError: if `port_int` is not passed. ValueError: if `port_int` is invalid. Examples: """

        port_int = kwargs.pop('port_int')
        callback = kwargs.pop('callback', self._callback)

        if re.search('^[0-9]{1,4}$', port_int) is None:
            raise ValueError('%s must be in the format of x for port channel '
                             'interfaces.' % repr(port_int))

        port_channel = getattr(self._interface, 'interface_port_channel_name')
        port_channel_args = dict(name=port_int)

        config = port_channel(**port_channel_args)

        delete_channel = config.find('.//*port-channel')
        delete_channel.set('operation', 'delete')

        return callback(config)