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: nullable_float64.go
    path of file: ./repos/goHackTools/vendor/github.com/tkrajina/gpxgo/gpx
    
    the code of the file until where you have to start completion: // Copyright 2013, 2014 Peter Vasil, Tomo Krajina. All
// rights reserved. Use of this source code is governed
// by a BSD-style license that can be found in the
// LICENSE file.

package gpx

import (
	"encoding/xml"
	"fmt"
	"strconv"
	"strings"
)

//NullableFloat64 implements a nullable float64
type NullableFloat64 struct {
	data    float64
	notNull bool
}

//Nu
    
func (n *NullableFloat64) UnmarshalXML(d *xml.Decoder, start xml.StartElement) error {
	t, err := d.Token()
	if err != nil {
		n.SetNull()
		return nil
	}
	if charData, ok := t.(xml.CharData); ok {
		strData := strings.Trim(string(charData), " ")
		value, err := strconv.ParseFloat(strData, 64)
		if err != nil {
			n.SetNull()
			return nil
		}
		n.SetValue(value)
	}
	d.Skip()
	return nil
}