You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: set_statement.go
    path of file: ./repos/jet/postgres
    
    the code of the file until where you have to start completion: package postgres

import "github.com/go-jet/jet/v2/internal/jet"

// UNION effectively appends the result of sub-queries(select statements) into single query.
// It eliminates duplicate rows from its result.
func UNION(lhs, rhs jet.SerializerStatement, selects ...jet.SerializerStatement) setStatement {
	return newSetStatementImpl(union, fal
    
func newSetStatementImpl(operator string, all bool, selects []jet.SerializerStatement) setStatement {
	newSetStatement := &setStatementImpl{}
	newSetStatement.ExpressionStatement = jet.NewExpressionStatementImpl(Dialect, jet.SetStatementType, newSetStatement,
		&newSetStatement.setOperator)

	newSetStatement.setOperator.Operator = operator
	newSetStatement.setOperator.All = all
	newSetStatement.setOperator.Selects = selects
	newSetStatement.setOperator.Limit.Count = -1

	newSetStatement.setOperatorsImpl.parent = newSetStatement

	return newSetStatement
}