code: def listify(obj):
      """Wrap all non-list or tuple objects in a list.
  
      Provides a simple way to accept flexible arguments.
      """
      if obj is None:
          return []
      else:
          return (
              obj
              if isinstance(obj, (list, tuple, type(None)))
              else [obj]
          )
  
file_path: bambi/bambi/utils.py
imports: from typing import Sequence
  import ast
  import textwrap
  import formulae
  import numpy
  from bambi.transformations import HSGP
label_desc: Use image node_id 1 for calling a global function with example usage: listify(obj) and returns: list, unknown