What is the sentiment of this news? Please choose an answer from {strong negative/moderately negative/mildly negative/neutral/mildly positive/moderately positive/strong positive}.
Text: BERLIN (Reuters) -German union Verdi has called on staff at seven Amazon distribution centres to strike over Sunday evening's night shift in a bid to force the retailer to accept the union's sectoral collective bargaining agreement.
user
moderately negative
assistant