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: decoder.go
    path of file: ./repos/schema
    
    the code of the file until where you have to start completion: // Copyright 2012 The Gorilla Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package schema

import (
	"encoding"
	"errors"
	"fmt"
	"reflect"
	"strings"
)

// NewDecoder returns a new Decoder.
func NewDecoder() *Decoder {
	return &Decoder{cache: newCache()}
}

// Decoder decodes values from a map[string][]string to a struct.
type Decoder struct {
	cache             *cache
	zeroEmpty         bool
	ignoreUnknownKeys bool
}

// SetAliasTag changes the tag used to locate custom field aliases.
// The default tag is "schema".
func (d *Decoder) SetAliasTag(tag string) {
    
func (d *Decoder) Decode(dst interface{}, src map[string][]string) error {
	v := reflect.ValueOf(dst)
	if v.Kind() != reflect.Ptr || v.Elem().Kind() != reflect.Struct {
		return errors.New("schema: interface must be a pointer to struct")
	}
	v = v.Elem()
	t := v.Type()
	errors := MultiError{}
	for path, values := range src {
		if parts, err := d.cache.parsePath(path, t); err == nil {
			if err = d.decode(v, path, parts, values); err != nil {
				errors[path] = err
			}
		} else if !d.ignoreUnknownKeys {
			errors[path] = UnknownKeyError{Key: path}
		}
	}
	errors.merge(d.setDefaults(t, v))
	errors.merge(d.checkRequired(t, src))
	if len(errors) > 0 {
		return errors
	}
	return nil
}