code: def _get_series_result_type(result, objs=None):
      
      from pandas import SparseSeries, SparseDataFrame, DataFrame
  
      # concat Series with axis 1
      if isinstance(result, dict):
          # concat Series with axis 1
          if all(isinstance(c, (SparseSeries, SparseDataFrame))
                 for c in result.values()):
              return SparseDataFrame
          else:
              return DataFrame
  
      # otherwise it is a SingleBlockManager (axis = 0)
      if result._block.is_sparse:
          return SparseSeries
      else:
          return objs[0]._constructor
docs: return appropriate class of Series concat
      input is either dict or array-like