MediaWiki:Datatransclusion-bad-argument-by/qqq

Issued if a bad value was specified for the "by" argument, that is, an unknown key field was selected. Parameters:
 * $1 is the name of the data source
 * $2 is the value of the by argument
 * $3 is a list of all valid keys for this data source
 * $4 is the number of valid keys for this data source.