Py3 print function

#!/user/bin/python3
from typing import TextIO
from sys import stdout, stderr


_print_context: TextIO = stdout


def print(*values, sep: str = ' ', end: str = '\n', file: TextIO = None, flush: bool = False) -> int:
    out = _print_context if file is None else file
    c_length = out.write(sep.join(map(str, values)) + end)
    if flush:
        out.flush()
    return c_length


class p_switcher:
    _last_stream: TextIO
    _this_stream: TextIO

    def __init__(self, out: TextIO):
        self._last_stream = _print_context
        self._this_stream = out

    def __enter__(self):
        global _print_context
        _print_context = self._this_stream

    def __exit__(self, exc_type, exc_val, exc_tb):
        global _print_context
        _print_context = self._last_stream


if __name__ == '__main__':
    print('Hello World!')
    with p_switcher(stderr):
        print('Hi', 5, flush = True)
    print('This is', stdout, 'safe and sound.')