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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _make_token_async(scopes, service_account_id):
 """Get a fresh authentication token. Args: scopes: A list of scopes. service_account_id: Internal-use only. Raises: An ndb.Return with a tuple (token, expiration_time) where expiration_time is seconds since the epoch. """

  rpc = app_identity.create_rpc()
  app_identity.make_get_access_token_call(rpc, scopes, service_account_id)
  token, expires_at = yield rpc
  raise ndb.Return((token, expires_at))