Python 如何根据索引压缩单个数据帧

我有以下数据帧:

                    label scoreCTBIN004v1  scoreCTBIN003v1  scoreCTBIN001v1  
    Overall Stress Score              54              NaN              NaN     
            Stress Score              50              NaN              NaN     
  Short-Term Stress Risk              50              NaN              NaN
      Future Stress Risk              59              NaN              NaN
     Chronic Stress Risk              55              NaN              NaN
    Overall Stress Score             NaN             57.0              NaN
            Stress Score             NaN             52.0              NaN
  Short-Term Stress Risk             NaN             52.0              NaN
      Future Stress Risk             NaN             65.0              NaN
     Chronic Stress Risk             NaN             59.0              NaN
    Overall Stress Score             NaN              NaN             57.0
            Stress Score             NaN              NaN             49.0
  Short-Term Stress Risk             NaN              NaN             54.0 
      Future Stress Risk             NaN              NaN             66.0 
     Chronic Stress Risk             NaN              NaN             60.0      

我只是想压缩标签列，使它们都在同一行上，但它不会合并标签，即使它们是相同的名称？

简单地说:

                    label scoreCTBIN004v1  scoreCTBIN003v1  scoreCTBIN001v1  
    Overall Stress Score              54              57              57     
            Stress Score              50              52              49     
  Short-Term Stress Risk              50              52              54
      Future Stress Risk              59              65              66
     Chronic Stress Risk              55              59              60