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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def set_prop_if_null(name, props, if_null):
 # type: (str, Dict[str, Any], Any) -> None """ Updates the value of a property if the previous one was None :param name: Name of the property :param props: Dictionary of properties :param if_null: Value to insert if the previous was None """

    value = get_prop_value(name, props)
    if value is None:
        props[name] = if_null