docs: def validate_lun_path(self, host_wwpn, host_port, wwpn, lun):
          """
          Validate if an FCP storage volume on an actual storage subsystem is
          reachable from this CPC, through a specified host port and using
          a specified host WWPN.
  
          This method performs the "Validate LUN Path" HMC operation.
  
          If the volume is reachable, the method returns. If the volume is not
          reachable (and no other errors occur), an :exc:`~zhmcclient.HTTPError`
          is raised, and its :attr:`~zhmcclient.HTTPError.reason` property
          indicates the reason as follows:
  
          * 484: Target WWPN cannot be reached.
          * 485: Target WWPN can be reached, but LUN cannot be reached.
  
          The CPC must have the "dpm-storage-management" feature enabled.
  
          Parameters:
  
            host_wwpn (:term:`string`):
              World wide port name (WWPN) of the host (CPC),
              as a hexadecimal number of up to 16 characters in any lexical case.
  
              This may be the WWPN of the physical storage port, or a WWPN of a
              virtual HBA. In any case, it must be the kind of WWPN that is used
              for zoning and LUN masking in the SAN.
  
            host_port (:class:`~zhmcclient.Port`):
              Storage port on the CPC that will be used for validating
              reachability.
  
            wwpn (:term:`string`):
              World wide port name (WWPN) of the FCP storage subsystem containing
              the storage volume,
              as a hexadecimal number of up to 16 characters in any lexical case.
  
            lun (:term:`string`):
              Logical Unit Number (LUN) of the storage volume within its FCP
              storage subsystem,
              as a hexadecimal number of up to 16 characters in any lexical case.
  
          Authorization requirements:
  
          * Object-access permission to the storage group owning this storage
            volume.
          * Task permission to the "Configure Storage - Storage Administrator"
            task.
  
          Raises:
  
            :exc:`~zhmcclient.HTTPError`
            :exc:`~zhmcclient.ParseError`
            :exc:`~zhmcclient.AuthError`
            :exc:`~zhmcclient.ConnectionError`
          """
  
          # The operation requires exactly 16 characters in lower case
          host_wwpn_16 = format(int(host_wwpn, 16), '016x')
          wwpn_16 = format(int(wwpn, 16), '016x')
          lun_16 = format(int(lun, 16), '016x')
  
          body = {
              'host-world-wide-port-name': host_wwpn_16,
              'adapter-port-uri': host_port.uri,
              'target-world-wide-port-name': wwpn_16,
              'logical-unit-number': lun_16,
          }
          self.manager.session.post(
              self.uri + '/operations/validate-lun-path',
              body=body)