docs: @Override
  	public CashbillInfo[] getInfos(String CorpNum, String[] MgtKeyList)
  			throws PopbillException {
  		if (MgtKeyList == null || MgtKeyList.length == 0)
  			throw new PopbillException(-99999999, "관리번호배열이 입력되지 않았습니다.");
  
  		String PostData = toJsonString(MgtKeyList);
  
  		return httppost("/Cashbill/States", CorpNum, PostData,
  				null, CashbillInfo[].class);
  	}