Выдает ошибку statistics.statisticserror mean requires at least one data point в коде

У меня выдает ошибку statistics.statisticserror mean requires at least one data point в коде. Что делать?

import statistics


def ReadData(Count):

  print('Enter Student parameters: gender (G/B (Upper case!)),  surname, height and weight. Use "space" to split data\nStrictly follow input order!\n')

  for _ in range(Count):

    rawData = input().split(' ')

  yield {'gender': rawData[0],'surname':rawData[1], 'height':int(rawData[2]), 'weight':int(rawData[3])}

def IsolateParameter(Container, Attribute):

    for LocCont in Container:

      yield LocCont[Attribute]


def StatAverage(Cont, Attribute, StatFunc):

  return StatFunc(list(IsolateParameter(Cont, Attribute)))

def GetTopHeight(Cont):

  return max(list(IsolateParameter(Cont, 'height')))


def main():

  RawData = ReadData(int(input('Count of Students:\n')))

  ListedData = list(RawData)

  AllBoys = filter(lambda g: g['gender'] == 'B', ListedData)

  AllGirls = filter(lambda g: g['gender'] == 'G', ListedData)

  AvBoyWeight = StatAverage(AllBoys, 'weight', statistics.mean)

  AvGirlsHeight = StatAverage(AllGirls, 'height', statistics.mean)

  TopHeightSurname = GetTopHeight(ListedData)

  print('''

  Average Boys weight: {0};

  Average Girls height: {1};

  Surname of tallest student: {2}

  '''.format(AvBoyWeight, AvGirlsHeight, TopHeightSurname))

if __name__ == '__main__':

  main()