old_contents: from checksum import file_sha1sum
  
  
  class AnalysisFile(object):
      def __init__(self, filename):
          self.filename = filename
  
      def checksum(self):
          return file_sha1sum(self.filename)
  
new_contents: from utils import file_sha1sum
  
  
  class AnalysisFile(object):
      def __init__(self, filename):
          self.filename = filename
  
      def checksum(self):
          return file_sha1sum(self.filename)
  
subject: Fix defunct import of checksum module