input: Write a function to compress a given data sequence by grouping consecutive numbers with the same sign. Return the compressed sequence as a list of lists where each sublist contains consecutive numbers with the same sign. If the input array is empty, return an empty list.
  assert compress_sequence([9, -2, 6, 0, -7])==[[9], [-2], [6, 0], [-7]]
  assert compress_sequence([1, 2, 3, -1, -2, -3])==[[1, 2, 3], [-1, -2, -3]]
  assert compress_sequence([0, 0, 0])==[[0, 0, 0]]
  assert compress_sequence([])==[]
output: def compress_sequence(data):
      if not data:
          return []
      result = []
      current_group = [data[0]]
      
      for num in data[1:]:
          if (num >= 0 and current_group[-1] >= 0) or (num < 0 and current_group[-1] < 0):
              current_group.append(num)
          else:
              result.append(current_group)
              current_group = [num]
      
      result.append(current_group)
      return result