code: function unmarshall(value) {
    var err;
    try {
      value = JSON.parse(value);
    } catch (e) {
      value = (typeof value === 'string') ? value.substr(0, 50) : '';
      err = new MarshallingError('Failed to marshall value: ' + value, e);
    }
    return {error: err, value: value};
  }
docs: Unmarshall a previously marshalled value
  back to its original type / state.
  
  @param {String} value - marshalled
  @return {Object}