code: func (fn *FieldValueFactorFunction) Weight(weight float64) *FieldValueFactorFunction {
  	fn.weight = &weight
  	return fn
  }
docs: // Weight adjusts the score of the score function.
  // See https://www.elastic.co/guide/en/elasticsearch/reference/7.0/query-dsl-function-score-query.html#_using_function_score
  // for details.