def datastore_start_cmd(port, assignment_options):
  """ Prepares command line arguments for starting a new datastore server.

  Args:
    port: An int - tcp port to start datastore server on.
    assignment_options: A dict containing assignment options from ZK.
  Returns:
    A list of command line arguments.
  """
  start_cmd = ['appscale-datastore',
               '--type', assignment_options.get('backend', 'cassandra'),
               '--port', str(port)]
  if assignment_options.get('verbose'):
    start_cmd.append('--verbose')
  return start_cmd