code: func (fn *FieldValueFactorFunction) Modifier(modifier string) *FieldValueFactorFunction {
  	fn.modifier = modifier
  	return fn
  }
docs: // Modifier to apply to the field value. It can be one of: none, log, log1p,
  // log2p, ln, ln1p, ln2p, square, sqrt, or reciprocal. Defaults to: none.