docs: def create_fa(self):
          """Create a FASTA file with extracted sequences.
  		"""
  
          if self._seqs is None:
              os.symlink(self._fa0_fn, self._fa_fn)
          else:
              in_seqs = pyfaidx.Fasta(self._fa0_fn)
  
              with open(self._fa_fn, "w+") as g:
                  for seq_desc in self._seqs:
                      x = in_seqs[seq_desc]
                      name, seq = x.name, str(x)
                      g.write(">" + name + "\n")
                      n = 80
                      seq_split = "\n".join([seq[i:i + n] for i in range(0, len(seq), n)])
                      g.write(seq_split + "\n")