fix(sdk): Fix get_experiment when there are no experiments. Fixes kub…

…eflow#4176 (kubeflow#4177)

Signed-off-by: Ilias Katsakioris <elikatsis@arrikto.com>

sdk/python/kfp/_client.py

@@ -379,7 +379,7 @@ def get_experiment(self, experiment_id=None, experiment_name=None, namespace=Non
     while next_page_token is not None:
       list_experiments_response = self.list_experiments(page_size=100, page_token=next_page_token, namespace=namespace)
       next_page_token = list_experiments_response.next_page_token
-      for experiment in list_experiments_response.experiments:
+      for experiment in list_experiments_response.experiments or []:
         if experiment.name == experiment_name:
           return self._experiment_api.get_experiment(id=experiment.id)
     raise ValueError('No experiment is found with name {}.'.format(experiment_name))