watchCount is a member property of listingInfo for the python version of Finding API, but is not documented on this webpage:
developer.ebay.com/Devzone/finding/CallRef/findItemsByCategory.html#Output I suggest updating the page for other developers top know this. There are a number of member properties of the response object using the ebaySDK that sometimes are not returned, like handling time or secondary category ID response.reply.searchResult.item[item_count].secondaryCategory.categoryId My suggestions is to always return all object member property field, even if empty or not applicable. Otherwise developers have to insert a bunch of try-except blocks to catch these non-returned fields (as they learn about them piecemeal) and avoid script errors and stoppage. Just assign it a None value. Thanks.