How to pick minimum value of an attribute from soap response and pick next node value based on it

//Using this expectedStayInfo  just for testing
def expectedStayInfo = [AmountAfterTax: 144.06, HotelCode: '03062', ChainCode: 'ABC' ]

def xml = new XmlSlurper().parseText(response)
def stays = xml.'**'.findAll {it.name() == 'RoomStay'}
def actualStayInfo = [AmountAfterTax: 0, HotelCode: null, ChainCode: null]

def updateActualStayInfo = { node, rate  -> 
  def isUpdate = false
  if ((0 == actualStayInfo.AmountAfterTax) || (actualStayInfo.AmountAfterTax > rate)) { 
    isUpdate = true
  }
  if (isUpdate) {
    def info = node.'**'.find{'BasicPropertyInfo' == it.name()}
    actualStayInfo.AmountAfterTax = rate
    actualStayInfo.HotelCode = info.@HotelCode.text()
    actualStayInfo.ChainCode = info.@ChainCode.text()
  }
}

stays.each { stay ->
  def tempMin = stay.'**'.findAll{it.name() == 'Base'}*.@AmountAfterTax.collect{it.toBigDecimal()}.min()
  updateActualStayInfo(stay, tempMin)
}

//test if the actual value of xml is matching
assert actualStayInfo == expectedStayInfo