Wrap HTTP method value in a bs3 label.

def http_method_formatter(view, context, model, name):
    """Wrap HTTP method value in a bs3 label."""
    method_map = {
        'GET': 'label-success',
        'PUT': 'label-info',
        'POST': 'label-primary',
        'DELETE': 'label-danger',
    }
    return Markup(
        '<span class="label {}">{}</span>'.format(
            method_map.get(model[name], 'label-default'), model[name]
        )
    )