code: def added(self):
          '''
          Returns all keys that have been added.
  
          If the keys are in child dictionaries they will be represented with
          . notation
          '''
          def _added(diffs, prefix):
              keys = []
              for key in diffs.keys():
                  if isinstance(diffs[key], dict) and 'old' not in diffs[key]:
                      keys.extend(_added(diffs[key],
                                         prefix='{0}{1}.'.format(prefix, key)))
                  elif diffs[key]['old'] == self.NONE_VALUE:
                      if isinstance(diffs[key]['new'], dict):
                          keys.extend(
                              _added(diffs[key]['new'],
                                     prefix='{0}{1}.'.format(prefix, key)))
                      else:
                          keys.append('{0}{1}'.format(prefix, key))
              return keys
  
          return sorted(_added(self._diffs, prefix='')f added(self):
          '''
          Returns all keys that have been added.
  
          If the keys are in child dictionaries they will be represented with
          . notation
          '''
          def _added(diffs, prefix):
              keys = []
              for key in diffs.keys():
                  if isinstance(diffs[key], dict) and 'old' not in diffs[key]:
                      keys.extend(_added(diffs[key],
                                         prefix='{0}{1}.'.format(prefix, key)))
                  elif diffs[key]['old'] == self.NONE_VALUE:
                      if isinstance(diffs[key]['new'], dict):
                          keys.extend(
                              _added(diffs[key]['new'],
                                     prefix='{0}{1}.'.format(prefix, key)))
                      else:
                          keys.append('{0}{1}'.format(prefix, key))
              return keys
  
          return sorted(_added(self._diffs, prefix=''))
docs: Returns all keys that have been added.
  
          If the keys are in child dictionaries they will be represented with
          . notation