parameters: (self)
docstring: return one dict which contains "data" and "label"
docstring_summary: return one dict which contains "data" and "label"
docstring_tokens: return one dict which contains data and label
function: def next(self):
          """return one dict which contains "data" and "label" """
          if self.iter_next():
              self.data, self.label = self._read()
              return {self.data_name  :  self.data[0][1],
                      self.label_name :  self.label[0][1]}
          else:
              raise StopIteration
function_tokens: def next ( self ) : if self . iter_next ( ) : self . data , self . label = self . _read ( ) return { self . data_name : self . data [ 0 ] [ 1 ] , self . label_name : self . label [ 0 ] [ 1 ] } else : raise StopIteration