code: public static void writeNucleotideSequence(OutputStream outputStream, Collection<DNASequence> dnaSequences) throws Exception {
  		FastaWriter<DNASequence, NucleotideCompound> fastaWriter = new FastaWriter<DNASequence, NucleotideCompound>(
  				outputStream, dnaSequences,
  				new GenericFastaHeaderFormat<DNASequence, NucleotideCompound>());
  		fastaWriter.process();
  
  	}
docs: Write a collection of NucleotideSequences to a file
  @param outputStream
  @param dnaSequences
  @throws Exception