Task: Categorize the tweet's emotional expression, classifying 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 reflect the tweeter's state of mind.
Tweet: @MendipHillsAONB do we think the swallows and swifts have gone? Photo'd 3 nights ago, not seen since. #sad #Autumn
This tweet contains emotions: 
pessimism, sadness