input: Write a python function to label data based on even and odd values in each sublist.
  assert label_data([[1, 2], [3, 4, 5], [6, 7, 8, 9]]) == ['OE', 'OOE', 'EOEO']
  assert label_data([[10, 15, 20], [25, 30], [35, 40, 45, 50]]) == ['EOE', 'OE', 'OEOE']
  assert label_data([[2, 4, 6], [1, 3, 5], [0, 9]]) == ['EEE', 'OOO', 'EO']
output: def label_data(data):
      result = []
      for sublist in data:
          label = ''.join(['E' if num % 2 == 0 else 'O' for num in sublist])
          result.append(label)
      return result