code: def _AssertDataIsList(key, lst):
    
  
    # list and tuple are supported.  Not supported are direct strings
    # and dictionary; these indicate too much or two little structure.
    if not isinstance(lst, list) and not isinstance(lst, tuple):
      raise NotAListError('%s must be a list' % key)
  
    # each list entry must be a string
    for element in lst:
      if not isinstance(element, str):
        raise ElementNotAStringError('Unsupported list element %s found in %s',
                                     (element, lst))
docs: Assert that lst contains list data and is not structured.