code: def get_exchanges(self, vhost=None):
          
          if vhost:
              vhost = quote(vhost, '')
              path = Client.urls['exchanges_by_vhost'] % vhost
          else:
              path = Client.urls['all_exchanges']
  
          exchanges = self._call(path, 'GET')
          return exchanges
docs: :returns: A list of dicts
          :param string vhost: A vhost to query for exchanges, or None (default),
              which triggers a query for all exchanges in all vhosts.