code: def core(self, key, value):
      
      core = self.get('core')
      deleted = self.get('deleted')
      project_type = self.get('project_type', [])
  
      if not core:
          normalized_a_values = [el.upper() for el in force_list(value.get('a'))]
          if 'CORE' in normalized_a_values:
              core = True
  
      if not deleted:
          normalized_c_values = [el.upper() for el in force_list(value.get('c'))]
          if 'DELETED' in normalized_c_values:
              deleted = True
  
      if not project_type:
          normalized_a_values = [el.upper() for el in force_list(value.get('a'))]
          if 'ACCELERATOR' in normalized_a_values:
              project_type.append('accelerator')
  
      self['project_type'] = project_type
      self['deleted'] = deleted
      return core
docs: Populate the ``core`` key.
  
      Also populates the ``deleted`` and ``project_type`` keys through side
      effects.