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: unmarshal.go
    path of file: ./repos/scan4all/vendor/github.com/pion/sdp/v3
    
    the code of the file until where you have to start completion: package sdp

import (
	"errors"
	"fmt"
	"net/url"
	"strconv"
	"strings"
)

var (
	errSDPInvalidSyntax       = errors.New("sdp: invalid synt
    
func s10(l *lexer) (stateFn, error) {
	return l.handleType(func(key string) stateFn {
		switch key {
		case "e=":
			return unmarshalEmail
		case "p=":
			return unmarshalPhone
		case "c=":
			return unmarshalSessionConnectionInformation
		case "b=":
			return unmarshalSessionBandwidth
		case "t=":
			return unmarshalTiming
		}
		return nil
	})
}