How to use the psiturk.models.Participant.query.all function in PsiTurk

@custom_code.route('/view_data')
@myauth.requires_auth
def list_my_data():
        users = Participant.query.all()
	try:
		return render_template('list.html', participants=users)
	except TemplateNotFound:
		abort(404)

@custom_code.route('/view_data')
@myauth.requires_auth
def list_my_data():
    users = Participant.query.all()
    try:
        return render_template('list.html', participants=users)
    except TemplateNotFound:
        abort(404)

@custom_code.route('/view_data')
@myauth.requires_auth
def list_my_data():
    users = Participant.query.all()
    try:
        return render_template('list.html', participants=users)
    except TemplateNotFound:
        abort(404)

def do_download_datafiles(self, _):
        ''' Download datafiles. '''
        contents = {"trialdata": lambda p: p.get_trial_data(), "eventdata":
                    lambda p: p.get_event_data(), "questiondata": lambda p:
                    p.get_question_data()}
        query = Participant.query.all()
        for k in contents:
            ret = "".join([contents[k](p) for p in query])
            temp_file = open(k + '.csv', 'w')
            temp_file.write(ret)
            temp_file.close()