code: def __init__(self):
      msg = (
          "Metaflow could not determine your user name based on "
          "environment variables ($USERNAME etc.)"
      )
      super(MetaflowUnknownUser, self).__init__(msg)
  
imports: import sys
  import traceback
label_desc: Use image node_id 1 to create a new MetaflowUnknownUser object from inherited base classes: MetaflowException with example: obj = MetaflowUnknownUser()