code: def _multi_lines(self, strands, permutation):
          '''Prepares lines to write to file for pfunc command input.
  
          :param strand: Strand input (cr.DNA or cr.RNA).
          :type strand: cr.DNA or cr.DNA
          :param permutation: Permutation (e.g. [1, 2, 3, 4]) of the type used
                              by pfunc_multi.
          :type permutation: list
          '''
          lines = []
          # Write the total number of distinct strands
          lines.append(str(len(strands)))
          # Write the distinct strands
          lines += [str(strand) for strand in strands]
          # Write the permutation
          lines.append(' '.join(str(p) for p in permutation))
  
          return linef _multi_lines(self, strands, permutation):
          '''Prepares lines to write to file for pfunc command input.
  
          :param strand: Strand input (cr.DNA or cr.RNA).
          :type strand: cr.DNA or cr.DNA
          :param permutation: Permutation (e.g. [1, 2, 3, 4]) of the type used
                              by pfunc_multi.
          :type permutation: list
          '''
          lines = []
          # Write the total number of distinct strands
          lines.append(str(len(strands)))
          # Write the distinct strands
          lines += [str(strand) for strand in strands]
          # Write the permutation
          lines.append(' '.join(str(p) for p in permutation))
  
          return lines
docs: Prepares lines to write to file for pfunc command input.
  
          :param strand: Strand input (cr.DNA or cr.RNA).
          :type strand: cr.DNA or cr.DNA
          :param permutation: Permutation (e.g. [1, 2, 3, 4]) of the type used
                              by pfunc_multi.
          :type permutation: list