parameters: (self, alias)
docstring: get `BatchGraph`s by given alias. Alias must be an element 
      in `SubKeys`.
docstring_summary: get `BatchGraph`s by given alias. Alias must be an element 
      in `SubKeys`.
docstring_tokens: get BatchGraph s by given alias . Alias must be an element in SubKeys .
function: def get_batchgraph(self, alias):
      """get `BatchGraph`s by given alias. Alias must be an element 
      in `SubKeys`.
      """
      pos_graph = BatchGraph.from_tensors(self._values[0:self.pos_size], 
        (self._dag.get_node(SubKeys.POS_SRC).type, 
         self._dag.get_node(SubKeys.POS_SRC).decoder),
        additional_keys = self._additional_keys)
      neg_graph = None
      if SubKeys.NEG_DST in self._dag.list_alias():
        neg_graph = BatchGraph.from_tensors(self._values[self.pos_size:],
          (self._dag.get_node(SubKeys.POS_SRC).type, 
           self._dag.get_node(SubKeys.POS_SRC).decoder),
          additional_keys = self._additional_keys)
      if (alias == SubKeys.POS_SRC) or (alias == SubKeys.POS_DST):
        return pos_graph
      elif alias == SubKeys.NEG_DST:
        return neg_graph
      else:
        raise ValueError("alias must be one of [SubKeys.POS_SRC, " 
                         "SubKeys.POS_DST, SubKeys.NEG_DST]")
function_tokens: def get_batchgraph ( self , alias ) : pos_graph = BatchGraph . from_tensors ( self . _values [ 0 : self . pos_size ] , ( self . _dag . get_node ( SubKeys . POS_SRC ) . type , self . _dag . get_node ( SubKeys . POS_SRC ) . decoder ) , additional_keys = self . _additional_keys ) neg_graph = None if SubKeys . NEG_DST in self . _dag . list_alias ( ) : neg_graph = BatchGraph . from_tensors ( self . _values [ self . pos_size : ] , ( self . _dag . get_node ( SubKeys . POS_SRC ) . type , self . _dag . get_node ( SubKeys . POS_SRC ) . decoder ) , additional_keys = self . _additional_keys ) if ( alias == SubKeys . POS_SRC ) or ( alias == SubKeys . POS_DST ) : return pos_graph elif alias == SubKeys . NEG_DST : return neg_graph else : raise ValueError ( "alias must be one of [SubKeys.POS_SRC, " "SubKeys.POS_DST, SubKeys.NEG_DST]" )