def METHOD_NAME(METHOD_NAME):
    """expr(expression) -> value
    Safe Python expression evaluation
    Evaluates a string that contains an expression that only
    uses Python constants. This can be used to e.g. evaluate
    a numerical expression from an untrusted source.
    Examples:
        >>> expr("1+2")
        3
        >>> expr("[1,2]*2")
        [1, 2, 1, 2]
        >>> expr("__import__('sys').modules")
        Traceback (most recent call last):
        ...
        ValueError: opcode LOAD_NAME not allowed
    """
    c = test_expr(METHOD_NAME, _expr_codes)
    return eval(c)