def _properties_model_to_dict(properties):
    """
    Convert properties model to dict.

    Args:
        properties: Properties model.

    Returns:
        dict: Converted model.
    """
    result = {}
    for attr in properties.__dict__:
        value = getattr(properties, attr)

        if hasattr(value, "__module__") and "models" in value.__module__:
            value = _properties_model_to_dict(value)

        if not (value is None or (isinstance(value, dict) and not value)):
            result[attr] = value

    return result