code: def double_reaction_deletion(model, reaction_list1=None, reaction_list2=None,
                               method="fba", solution=None, processes=None,
                               **kwargs):
      
  
      reaction_list1, reaction_list2 = _element_lists(model.reactions,
                                                      reaction_list1,
                                                      reaction_list2)
      return _multi_deletion(
          model, 'reaction', element_lists=[reaction_list1, reaction_list2],
          method=method, solution=solution, processes=processes, **kwargs)
docs: Knock out each reaction pair from the combinations of two given lists.
  
      We say 'pair' here but the order order does not matter.
  
      Parameters
      ----------
      model : cobra.Model
          The metabolic model to perform deletions in.
      reaction_list1 : iterable, optional
          First iterable of ``cobra.Reaction``s to be deleted. If not passed,
          all the reactions from the model are used.
      reaction_list2 : iterable, optional
          Second iterable of ``cobra.Reaction``s to be deleted. If not passed,
          all the reactions from the model are used.
      method: {"fba", "moma", "linear moma", "room", "linear room"}, optional
          Method used to predict the growth rate.
      solution : cobra.Solution, optional
          A previous solution to use as a reference for (linear) MOMA or ROOM.
      processes : int, optional
          The number of parallel processes to run. Can speed up the computations
          if the number of knockouts to perform is large. If not passed,
          will be set to the number of CPUs found.
      kwargs :
          Keyword arguments are passed on to underlying simulation functions
          such as ``add_room``.
  
      Returns
      -------
      pandas.DataFrame
          A representation of all combinations of reaction deletions. The
          columns are 'growth' and 'status', where
  
          index : frozenset([str])
              The reaction identifiers that were knocked out.
          growth : float
              The growth rate of the adjusted model.
          status : str
              The solution's status.