docs: def getDiskSpace(self):
          """Get disk space information.
  
              >>> disk_info = nd.getDiskSpace()
  
          :return: ``metadata`` if success or ``error message``
  
          :metadata:
                - expandablespace
                - filemaxsize
                - largefileminsize
                - largefileunusedspace
                - largefileusedspace
                - paymentspace
                - totallargespace
                - totalspace
                - unusedspace
                - usedspace
          """
          data = {'userid': self.user_id,
                  'useridx': self.useridx,
                 }
          s, metadata = self.POST('getDiskSpace',data)
  
          if s is True:
              usedspace = byte_readable(metadata['usedspace'])
              totalspace = byte_readable(metadata['totalspace'])
              print "Capacity: %s / %s" % (usedspace, totalspace)
  
              return metadata
          else:
              print message