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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _parse_status_code(response):
 """ Return error string code if the response is an error, otherwise ``"OK"`` """


    # This happens when a status response is expected
    if isinstance(response, string_types):
        return response

    # This happens when a list of structs are expected
    is_single_list = isinstance(response, list) and len(response) == 1
    if is_single_list and isinstance(response[0], string_types):
        return response[0]

    # This happens when a struct of any kind is returned
    return "OK"