Task: Analyze the tweet's emotional connotations and classify it as either 'neutral or no emotion' or as one or more of the specified emotions (anger, anticipation, disgust, fear, joy, love, optimism, pessimism, sadness, surprise, trust) that best portray the tweeter's mental state.
Tweet: Harking back to 2012 - DT's challenge to @POTUS...I will give...DT a hearty thank you...if he will release his tax returns....
This tweet contains emotions: 
joy