How to find the android appID to use it for Admob on Corona

I include this plugin on the setttings based on the documentation:

plugins = { ["CoronaProvider.ads.admob"] = { -- required publisherId = "com.coronalabs", }, },  

and then in my application I have

ads.init( "admob", "ca-app-pub-8145556512349498/5075330363", adListener ) ads.show( "banner", { x=0, y=0 } )  

where ca-app-pub-8145556512349498/5075330363 is the Ad unit ID from Admob site, but I suppose is not correct, because this field should be the appId, how can I found this?

I believe others have said it is the Publisher ID number, but I’m not sure.  

corona admob plugin not working with new Ad unit ID?

Ad unit ID: ca-app-pub-XXXXXXXXXXXXXXXXXX/xxxxxxxxxxxxx

I believe others have said it is the Publisher ID number, but I’m not sure.  

corona admob plugin not working with new Ad unit ID?

Ad unit ID: ca-app-pub-XXXXXXXXXXXXXXXXXX/xxxxxxxxxxxxx