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: constraint_builder.go
    path of file: ./repos/cockroach/pkg/sql/opt/lookupjoin
    
    the code of the file until where you have to start completion: // Copyright 2022 The Cockroach Authors.
//
// Use of this software is governed by the Business Source License
// included in the 
    
func (b *ConstraintBuilder) constructColEquality(leftCol, rightCol opt.ColumnID) memo.FiltersItem {
	var filters memo.FiltersItem
	// Disable normalization rules when constructing the lookup expression so
	// that it does not get normalized into a non-canonical expression.
	b.f.DisableOptimizationsTemporarily(func() {
		filters = b.f.ConstructFiltersItem(
			b.f.ConstructEq(
				b.f.ConstructVariable(leftCol),
				b.f.ConstructVariable(rightCol),
			),
		)
	})
	return filters
}