docs: def extract_dmg(self, path='.'):
          """
          Extract builds with .dmg extension
  
          Will only work if `hdiutil` is available.
  
          @type path:
          @param path:
          """
          dmg_fd, dmg_fn = tempfile.mkstemp(prefix='fuzzfetch-', suffix='.dmg')
          os.close(dmg_fd)
          out_tmp = tempfile.mkdtemp(prefix='fuzzfetch-', suffix='.tmp')
          try:
              _download_url(self.artifact_url('dmg'), dmg_fn)
              if std_platform.system() == 'Darwin':
                  LOG.info('.. extracting')
                  subprocess.check_call(['hdiutil', 'attach', '-quiet', '-mountpoint', out_tmp, dmg_fn])
                  try:
                      apps = [mt for mt in os.listdir(out_tmp) if mt.endswith('app')]
                      assert len(apps) == 1
                      shutil.copytree(os.path.join(out_tmp, apps[0]), os.path.join(path, apps[0]), symlinks=True)
                  finally:
                      subprocess.check_call(['hdiutil', 'detach', '-quiet', out_tmp])
              else:
                  LOG.warning('.. can\'t extract target.dmg on %s', std_platform.system())
                  shutil.copy(dmg_fn, os.path.join(path, 'target.dmg'))
          finally:
              shutil.rmtree(out_tmp, onerror=onerror)
              os.unlink(dmg_fn)