def builder_support(builder):
    """Return True when builder is supported. Supported builders output in
    html format, but exclude `PickleHTMLBuilder` and `JSONHTMLBuilder`,
    which run into issues when serializing blog objects."""

    if hasattr(builder, 'builder'):
        builder = builder.builder

    not_supported = set(['json', 'pickle'])
    return builder.format == 'html' and not builder.name in not_supported