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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 get_queues(self, vhost=None):
 """ Get all queues, or all queues in a vhost if vhost is not None. Returns a list. :param string vhost: The virtual host to list queues for. If This is None (the default), all queues for the broker instance are returned. :returns: A list of dicts, each representing a queue. :rtype: list of dicts """

        if vhost:
            vhost = quote(vhost, '')
            path = Client.urls['queues_by_vhost'] % vhost
        else:
            path = Client.urls['all_queues']

        queues = self._call(path, 'GET')
        return queues or list()