input: def compress_sequence(nums):
      """
      Compresses a given data sequence by grouping consecutive numbers with the same sign together.
      If two consecutive numbers have the same sign (both positive or both negative), they are grouped together.
      If they have different signs, they are considered separate groups.
  
      >>> compress_sequence([9, -2, 6, 0, -7])
      [[9], [-2, 6, 0], [-7]]
      """
      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
  
  print(compress_sequence([9, -2, 6, 0, -7]))
output:     output = []
      temp = [nums[0]]
  
      for i in range(1, len(nums)):
          if nums[i-1] * nums[i] >= 0:
              temp.append(nums[i])
          else:
              output.append(temp)
              temp = [nums[i]]
      output.append(temp)
  
      return output