code: func (h *Client) ProductPosition(productPosition int64) *Client {
  	h.productPosition = productPosition
  	h.productPositionSet = true
  	return h
  }
docs: // The product's position in a list or collection. Product
  // index must be a positive integer between 1 and 200, inclusive.
  // For analytics.js the Enhanced Ecommerce plugin must be installed
  // before using this field.