code: def proceedings(self, key, value):
      
      proceedings = self.get('proceedings')
      refereed = self.get('refereed')
  
      if not proceedings:
          normalized_a_values = [el.upper() for el in force_list(value.get('a'))]
          if 'PROCEEDINGS' in normalized_a_values:
              proceedings = True
  
      if not refereed:
          normalized_a_values = [el.upper() for el in force_list(value.get('a'))]
          if 'PEER REVIEW' in normalized_a_values:
              refereed = True
          elif 'NON-PUBLISHED' in normalized_a_values:
              refereed = False
  
      self['refereed'] = refereed
      return proceedings
docs: Populate the ``proceedings`` key.
  
      Also populates the ``refereed`` key through side effects.