code: function orderBy(dimension, direction) {
    if (arguments.length === 1) {
      direction = 'ASCENDING'
    }
  
    if (!dimension) {
      throw new FieldError('Dimension is not specified')
    }
    else if (!~['ascending', 'descending'].indexOf(direction.toLowerCase())) {
      throw new FieldError('Bad orderBy direction: ' + direction)
    }
  
    return {
      dimension: dimension,
      direction: direction
    }
  }
docs: Set orderBy spec
  
  @param {string} dimension Dimension to sort by
  @param {string} direction Sorting direction
  @returns {object}