code: def get_cgi_parameter_str(form: cgi.FieldStorage,
                            key: str,
                            default: str = None) -> str:
      
      paramlist = form.getlist(key)
      if len(paramlist) == 0:
          return default
      return paramlist[0]
docs: Extracts a string parameter from a CGI form.
      Note: ``key`` is CASE-SENSITIVE.