code: def wwpn_alloc(self):
          
          wwpn_int = self._wwpn_pool.alloc()
          wwpn = "AFFEAFFE0000" + "{:04X}".format(wwpn_int)
          return wwpn
docs: Allocates a WWPN unique to this partition, in the range of
          0xAFFEAFFE00008000 to 0xAFFEAFFE0000FFFF.
  
          Returns:
            string: The WWPN as 16 hexadecimal digits in upper case.
  
          Raises:
            ValueError: No more WWPNs available in that range.