How to use the makefun.main._SymbolRef function in makefun

"""
    Helper method for signature symbols (defaults, type hints) protection.

    Returns either `val`, or a protection symbol. In that case the protection symbol
    is created with name `varname` and inserted into `evaldict`

    :param val:
    :param needs_protection:
    :param varname:
    :param evaldict:
    :return:
    """
    if needs_protection:
        # store the object in the evaldict and insert name
        evaldict[varname] = val
        return _SymbolRef(varname)
    else:
        return val