code: def _read_content_or_path(content_or_path):
      
      if "\n" in content_or_path.strip():
          return content_or_path
  
      if not os.path.exists(content_or_path):
          raise IOError("File '%s' doesn't exists!" % content_or_path)
  
      with open(content_or_path) as f:
          return f.read()
docs: If `content_or_path` contains ``\\n``, return it. Else assume, that it is
      path and read file at that path.
  
      Args:
          content_or_path (str): Content or path to the file.
  
      Returns:
          str: Content.
  
      Raises:
          IOError: whhen the file is not found.