code: def tar_to_bigfile(self, fname, outfile):
          
          fnames = []
          tmpdir = mkdtemp()
          
          # Extract files to temporary directory
          with tarfile.open(fname) as tar:
              tar.extractall(path=tmpdir)
          for root, _, files in os.walk(tmpdir):
              fnames += [os.path.join(root, fname) for fname in files]
          
          # Concatenate
          with open(outfile, "w") as out:
              for infile in fnames:
                  for line in open(infile):
                      out.write(line)
                  os.unlink(infile)
          
          # Remove temp dir
          shutil.rmtree(tmpdir)
docs: Convert tar of multiple FASTAs to one file.