code: func (db *DB) statement(sql string) (*sql.Stmt, error) {
  	if db.connection == nil {
  		return nil, fmt.Errorf("Not connected to database")
  	}
  
  	sql = db.connection.Rebind(sql)
  	if _, ok := db.cache[sql]; !ok {
  		stmt, err := db.connection.Prepare(sql)
  		if err != nil {
  			return nil, err
  		}
  		db.cache[sql] = stmt
  	}
  
  	if q, ok := db.cache[sql]; ok {
  		return q, nil
  	}
  
  	return nil, fmt.Errorf("Weird bug: query '%s' is still not properly prepared", sql)
  }
docs: // Return the prepared statement for a given SQL query