def setAssignArgumentsWithDefault(arguments, argumentDefinition):
    """
    Set arguments not provided by the user with a default assign spec value,
    unless the default value is None (read don't set default).
    """
    for argument in argumentDefinition:
        if argument not in arguments and argumentDefinition[argument]['default'
            ] is not None:
            arguments[argument] = argumentDefinition[argument]['default']
    return
