rraval

    Python 3.9.13 (main, May 17 2022, 14:19:07)
    [GCC 11.3.0] on linux
    Type "help", "copyright", "credits" or "license" for more information.
    >>> import sys
    >>> sys.getrefcount(None)
    4584
    >>> import ctypes
    >>> ctypes.pythonapi.Py_DecRef.argtypes = [ctypes.py_object]
    >>> for i in range(5000):
    ...     ctypes.pythonapi.Py_DecRef(None)
    ...
    0
    0
    0
    0
    0
    [snip]
    Fatal Python error: none_dealloc: deallocating None
    Python runtime state: initialized

    Current thread 0x00007f28b22b7740 (most recent call first):
      File "<stdin>", line 2 in <module>
    fish: Job 1, 'python3' terminated by signal SIGABRT (Abort)

    class AlphaNumericString {
        private final String str;

        // use a fallible factory with a `private` constructor if you're
        // morally opposed to exceptions
        public AlphaNumericString(String str) throws AlphaNumericException {
            if (!str.matches("^[a-zA-Z0-9]*$")) {
                throw new AlphaNumericException();
            }

            this.str = str;
        }

        private static class AlphaNumericException extends Exception {
        }
    }

    function f(x: any[]): [number, string] {
        return x;
    }

    Type 'any[]' is missing the following properties from type '[number, string]': 0, 1