Python Helm values seem to be ignored

[lblackstone]

from pulumi_kubernetes.helm.v2 import Chart, ChartOpts

cert_manager_chart_opts = ChartOpts(chart="jetstack/cert-manager")
cert_manager_chart_opts.values = \
    {
        'ingressShim':
            {
                'defaultIssuerName': 'letsencrypt-prod',
                'defaultIssuerKind': 'ClusterIssuer'
            },
        'webhook':
            {
                'enabled': False
            }
    }

# Deploy the cert manager.
cert_manager = Chart(
    "cert-manager",
    cert_manager_chart_opts)

The webhook should be disabled in this example, but is still being installed (the default).