text: """
  Utilities for Otter Run
  """
  
  import re
  import nbformat
  
  from ...utils import get_source
  
  def replace_notebook_instances(nb_path):
      """
      Replaces the creation of ``otter.Notebook`` instances in a notebook at ``nb_path`` that have custom 
      test paths with the default for Gradescope.
  
      Args:
          nb_path (``str``): path to the notebook
      """
      try:
          nb = nbformat.read(nb_path, as_version=nbformat.NO_CONVERT)
          script = False
      except nbformat.reader.NotJSONError:
          nb = nbformat.v4.new_notebook()
          with open(nb_path) as f:
              source = f.read()
          nb['cells'].append(nbformat.v4.new_code_cell(source))
          script = True
  
      instance_regex = r"otter.Notebook\([\"'].+[\"']\)"
      for cell in nb['cells']:
          source = get_source(cell)
          for i, line in enumerate(source):
              line = re.sub(instance_regex, "otter.Notebook()", line)
              source[i] = line
          cell['source'] = "\n".join(source)
  
      if not script:
          nbformat.write(nb, nb_path)
      else:
          source = get_source(nb['cells'][0])
          with open(nb_path, "w") as f:
              f.write("\n".join(source))
  