def insert_pure_function(module, fnty, name):
    """
    Insert a pure function (in the functional programming sense) in the
    given module.
    """
    fn = get_or_insert_function(module, fnty, name)
    fn.attributes.add("readonly")
    fn.attributes.add("nounwind")
    return fn

    Insert a pure function (in the functional programming sense) in the
    given module.
    
numba/core/cgutils.py