docs: def _compile_mothur_script(self):
          """Returns a Mothur batch script as a string"""
          def format_opts(*opts):
              """Formats a series of options for a Mothur script"""
              return ', '.join(filter(None, map(str, opts)))
          vars = {
              'in': self._input_filename,
              'unique': self._derive_unique_path(),
              'dist': self._derive_dist_path(),
              'names': self._derive_names_path(),
              'cluster_opts': format_opts(
                  self.Parameters['method'],
                  self.Parameters['cutoff'],
                  self.Parameters['precision'],
              ),
          }
          script = (
              '#'
              'unique.seqs(fasta=%(in)s); '
              'dist.seqs(fasta=%(unique)s); '
              'read.dist(column=%(dist)s, name=%(names)s); '
              'cluster(%(cluster_opts)s)' % vars
          )
          return script