docs: def add_seqs_to_alignment(seqs, aln, moltype, params=None, accurate=False):
      """Returns an Alignment object from seqs and existing Alignment.
  
      seqs: a cogent.core.sequence.Sequence object, or data that can be used
      to build one.
  
      aln: an cogent.core.alignment.Alignment object, or data that can be used
      to build one
  
      params: dict of parameters to pass in to the Mafft app controller.
      """
      #create SequenceCollection object from seqs
      seq_collection = SequenceCollection(seqs,MolType=moltype)
      #Create mapping between abbreviated IDs and full IDs
      seq_int_map, seq_int_keys = seq_collection.getIntMap()
      #Create SequenceCollection from int_map.
      seq_int_map = SequenceCollection(seq_int_map,MolType=moltype)
  
      #create Alignment object from aln
      aln = Alignment(aln,MolType=moltype)
      #Create mapping between abbreviated IDs and full IDs
      aln_int_map, aln_int_keys = aln.getIntMap(prefix='seqn_')
      #Create SequenceCollection from int_map.
      aln_int_map = Alignment(aln_int_map,MolType=moltype)
  
      #Update seq_int_keys with aln_int_keys
      seq_int_keys.update(aln_int_keys)
  
      #Create Mafft app.
      app = Mafft(InputHandler='_input_as_multiline_string',\
          params=params,
          SuppressStderr=True)
  
      #Turn on correct moltype
      moltype_string = moltype.label.upper()
      app.Parameters[MOLTYPE_MAP[moltype_string]].on()
  
      #Do not report progress
      app.Parameters['--quiet'].on()
  
      #Add aln_int_map as seed alignment
      app.Parameters['--seed'].on(\
          app._tempfile_as_multiline_string(aln_int_map.toFasta()))
  
      #More accurate alignment, sacrificing performance.
      if accurate:
          app.Parameters['--globalpair'].on()
          app.Parameters['--maxiterate'].Value=1000
  
      #Get results using int_map as input to app
      res = app(seq_int_map.toFasta())
      #Get alignment as dict out of results
      alignment = dict(parse_fasta(res['StdOut']))
  
      #Make new dict mapping original IDs
      new_alignment = {}
      for k,v in alignment.items():
          key = k.replace('_seed_','')
          new_alignment[seq_int_keys[key]]=v
      #Create an Alignment object from alignment dict
      new_alignment = Alignment(new_alignment,MolType=moltype)
      #Clean up
      res.cleanUp()
      remove(app.Parameters['--seed'].Value)
      del(seq_collection,seq_int_map,seq_int_keys,\
          aln,aln_int_map,aln_int_keys,app,res,alignment)
  
      return new_alignment