code: func (m *Migrator) RollbackN(n int) error {
  	migrations := m.Migrations(Active)
  	if len(migrations) == 0 {
  		return nil
  	}
  
  	last_migration := len(migrations) - 1 - n
  
  	for i := len(migrations) - 1; i != last_migration; i-- {
  		if err := m.ApplyMigration(migrations[i], downMigration); err != nil {
  			return err
  		}
  	}
  
  	return nil
  }
docs: // Rolls back N migrations.