Evaluates integrity of the translator data frame, subsetting it to selected columns and removing duplicated rows.
validateTranslatorDf(df, sourceKey, targetKey)
| df | The translator data frame to validate.  | 
    
|---|---|
| sourceKey | Character indicating the column of the df where the source ids are stored.  | 
    
| targetKey | Character indicating the column of the df where the source ids are stored.  | 
    
The validated and ammended translator data frame if no problems are found.