code: def cell_language(source, default_language, custom_cell_magics):
      """Return cell language and language options, if any"""
      if source:
          line = source[0]
          if default_language == "csharp":
              if line.startswith("#!"):
                  lang = line[2:].strip()
                  if lang in _JUPYTER_LANGUAGES:
                      source.pop(0)
                      return lang, ""
          elif line.startswith("%%"):
              magic = line[2:]
              if " " in magic:
                  lang, magic_args = magic.split(" ", 1)
              else:
                  lang = magic
                  magic_args = ""
  
              if (
                  lang in _JUPYTER_LANGUAGES
                  or lang in custom_cell_magics
              ):
                  source.pop(0)
                  return lang, magic_args
  
      return None, None
  
label_desc: Use image node_id 5 for calling a global function with example usage: cell_language(source, default_language, custom_cell_magics) and returns: None,  None, lang,  str, lang,  magic_args