code: def add_empty_etd_ms_fields(etd_ms_dict):
      
      # Determine which ETD MS elements are missing from the etd_ms_dict.
      for element in ETD_MS_ORDER:
          if element not in etd_ms_dict:
              # Try to create an element with content and qualifier.
              try:
                  py_object = ETD_MS_CONVERSION_DISPATCH[element](
                      content='',
                      qualifier='',
                  )
              except:
                  # Try to create an element with content.
                  try:
                      py_object = ETD_MS_CONVERSION_DISPATCH[element](content='')
                  except:
                      # Try to create an element without content.
                      try:
                          py_object = ETD_MS_CONVERSION_DISPATCH[element]()
                      except:
                          raise PyuntlException(
                              'Could not add empty element field.'
                          )
                      else:
                          etd_ms_dict[element] = [{'content': {}}]
                  else:
                      # Handle element without children.
                      if not py_object.contained_children:
                          etd_ms_dict[element] = [{'content': ''}]
                      else:
                          etd_ms_dict[element] = [{'content': {}}]
              else:
                  # Handle element without children.
                  if py_object:
                      if not py_object.contained_children:
                          etd_ms_dict[element] = [{'content': '',
                                                   'qualifier': ''}]
                  else:
                      etd_ms_dict[element] = [{'content': {},
                                               'qualifier': ''}]
              # Add empty contained children.
              if py_object:
                  for child in py_object.contained_children:
                      etd_ms_dict[element][0].setdefault('content', {})
                      etd_ms_dict[element][0]['content'][child] = ''
      return etd_ms_dict
docs: Add empty values for ETD_MS fields that don't have values.