input: def compress_sequence(nums):
      """ Compress a given data sequence by grouping consecutive numbers that have the 
      same sign or are zero together. If consecutive numbers have different signs, 
      they should be grouped separately.
  
      >>> compress_sequence([9, -2, 6, 0, -7])
      [[9], [-2, 6, 0], [-7]]
      >>> compress_sequence([1, 2, 3, -1, -2, -3, 0, 0])
      [[1, 2, 3], [-1, -2, -3], [0, 0]]
      """
      output = []
      temp = []
  
      for i in range(1, len(nums)):
          if nums[i-1] * nums[i] >= 0:
              temp.append(nums[i-1])
          else:
              temp.append(nums[i-1])
              output.append(temp)
              temp = []
      temp.append(nums[i])
      output.append(temp)
  
      return output
output:     output = []
      temp = [nums[0]]
  
      for i in range(1, len(nums)):
          if nums[i] * nums[i-1] >= 0:
              temp.append(nums[i])
          else:
              output.append(temp)
              temp = [nums[i]]
      output.append(temp)
  
      return output