code: def _feature_to_fields(f, jsonify=True):
      
      x = []
      for k in constants._keys:
          v = getattr(f, k)
          if jsonify and (k in ('attributes', 'extra')):
              x.append(_jsonify(v))
          else:
              x.append(v)
      return tuple(x)
docs: Convert feature to tuple, for faster sqlite3 import