docs: def _to_rest_rels(model, props):
      """ Move the relationships to appropriate location in the props
  
      All to_ones should be in a to_one key while all to_manys
      should be in a to_many key.
      """
  
      props['to_many'] = {}
      props['to_one'] = {}
  
      for key in model.to_one:
          try:
              props['to_one'][key] = props.pop(key)
          except KeyError:
              continue
  
      for key in model.to_many:
          try:
              props['to_many'][key] = props.pop(key)
          except KeyError:
              continue