code: def _namespace_default():
      
      ns_path = '/var/run/secrets/kubernetes.io/serviceaccount/namespace'
      if os.path.exists(ns_path):
          with open(ns_path) as f:
              return f.read().strip()
      return 'default'
docs: Get current namespace if running in a k8s cluster
  
      If not in a k8s cluster with service accounts enabled, default to
      'default'
  
      Taken from https://github.com/jupyterhub/kubespawner/blob/master/kubespawner/spawner.py#L125