code: func (d *AggregateDsl) Cardinality(field string, rehash bool, threshold int) *AggregateDsl {
  	c := Cardinality{Field: field}
  
  	// Only set if it's false, since the default is true
  	if !rehash {
  		c.Rehash = false
  	}
  
  	if threshold > 0 {
  		c.PrecisionThreshold = float64(threshold)
  	}
  	d.Type = c
  	d.TypeName = "cardinality"
  	return d
  }
docs: /**
   * Cardinality(
   *	 "field_name",
   *	 true,
   *   0,
   * )
   */