docs: def upload(self, filename, number_of_hosts):
          """Upload the given file to the specified number of hosts.
  
          :param filename: The filename of the file to upload.
          :type filename: str
          :param number_of_hosts: The number of hosts to connect to.
          :type number_of_hosts: int
          :returns:  A list of dicts with 'host_name' and 'url' keys for all
                     successful uploads or an empty list if all uploads failed.
          :rtype: list
          """
          return self.multiupload(filename, self.random_hosts(number_of_hosts))