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: db.xo.go
    path of file: ./repos/xo/_examples/a_bit_of_everything/postgres
    
    the code of the file until where you have to start completion: package postgres

// Code generated by xo. DO NOT EDIT.

import (
	"context"
	"database/sql"
	"fmt"
	"io"
)

var (
	// logf is used by generated code to log 
    
func convLogger(logger interface{}) func(string, ...interface{}) {
	switch z := logger.(type) {
	case io.Writer:
		return func(s string, v ...interface{}) {
			fmt.Fprintf(z, s, v...)
		}
	case func(string, ...interface{}) (int, error): // fmt.Printf
		return func(s string, v ...interface{}) {
			_, _ = z(s, v...)
		}
	case func(string, ...interface{}): // log.Printf
		return z
	}
	panic(fmt.Sprintf("unsupported logger type %T", logger))
}