IEnumerable.distinct Method
        
 Returns distinct elements from a sequence by using the equality comparer to compare values.
 
         
        Parameters
        
            - equalityComparer
            
 
            - 
                
An equality comparer to compare join keys.
                
Optional: True 
        
        Return Value
        
Type: IEnumerable
        
An enumerable that contains distinct elements from the source sequence.