func (h Header) Get(key string) string {
	return textproto.MIMEHeader(h).Get(key)
}

var ErrHeaderNotPresent = errors.New("mail: header not in message")

// Date parses the Date header field.
func (h Header) Date() (time.Time, error) {
	hdr := h.Get("Date")
	if hdr == "" {
		return time.Time{}, ErrHeaderNotPresent
	}
	return ParseDate(hdr)
}

		{"(Header).Get", Method, 0},
		{"Address", Type, 0},
		{"Address.Address", Field, 0},
		{"Address.Name", Field, 0},
		{"AddressParser", Type, 5},
		{"AddressParser.WordDecoder", Field, 5},
		{"ErrHeaderNotPresent", Var, 0},
		{"Header", Type, 0},
		{"Message", Type, 0},
		{"Message.Body", Field, 0},
		{"Message.Header", Field, 0},
		{"ParseAddress", Func, 1},
		{"ParseAddressList", Func, 1},

pkg net/mail, type Header map[string][]string
pkg net/mail, type Message struct
pkg net/mail, type Message struct, Body io.Reader
pkg net/mail, type Message struct, Header Header
pkg net/mail, var ErrHeaderNotPresent error
pkg net/rpc, const DefaultDebugPath ideal-string
pkg net/rpc, const DefaultRPCPath ideal-string
pkg net/rpc, func Accept(net.Listener)
pkg net/rpc, func Dial(string, string) (*Client, error)