old_contents: class BaseCompare(object):
      def __init__(self, key):
          self.key = key
          self.value = None
          self.op = None
  
      def __eq__(self, other):
          self.value = other
          self.op = '='
          return self
  
      def __lt__(self, other):
          self.value = other
          self.op = '<'
          return self
  
      def __gt__(self, other):
          self.value = other
          self.op = '>'
          return self
  
      def __repr__(self):
          return "{}: {}('{}') {} '{}'".format(self.__class__, self.compare_type,
                                               self.key, self.op, self.value)
  
  
  
  class Value(BaseCompare):
      compare_type = 'value'
  
  
  class Version(BaseCompare):
      compare_type = 'version'
  
  
  class Put(object):
      def __init__(self, key, value):
          self.key = key
          self.value = value
  
new_contents: class BaseCompare(object):
      def __init__(self, key):
          self.key = key
          self.value = None
          self.op = None
  
      def __eq__(self, other):
          self.value = other
          self.op = '='
          return self
  
      def __lt__(self, other):
          self.value = other
          self.op = '<'
          return self
  
      def __gt__(self, other):
          self.value = other
          self.op = '>'
          return self
  
      def __repr__(self):
          return "{}: {}('{}') {} '{}'".format(self.__class__, self.compare_type,
                                               self.key, self.op, self.value)
  
  
  
  class Value(BaseCompare):
      compare_type = 'value'
  
  
  class Version(BaseCompare):
      compare_type = 'version'
  
  
  class Create(BaseCompare):
      compare_type = 'create'
  
  
  class Mod(BaseCompare):
      compare_type = 'mod'
  
  
  class Put(object):
      def __init__(self, key, value):
          self.key = key
          self.value = value
  
  
  class Get(object):
      def __init__(self, key):
          self.key = key
  
  
  class Delete(object):
      def __init__(self, key):
          self.key = key
  
subject: Add additional transaction types