docs: def _as_spl_expr(value):
      """ Return value converted to an SPL expression if
      needed other otherwise value.
      """
      import streamsx._streams._numpy
  
      if hasattr(value, 'spl_json'):
          return value
        
      if isinstance(value, Enum):
          value = streamsx.spl.op.Expression.expression(value.name)
  
      npcnv = streamsx._streams._numpy.as_spl_expr(value)
      if npcnv is not None:
          return npcnv
      
      return value