Ever been told strings are immutable in Python? I wanted to test that.

mutate_string.py

#! /usr/bin/env python3
def replace_contents(
        string: str,
        search_string: str,
        replace_string: str = "",
        global_replace: bool = False,
        terminate_char: str = ' ',
        return_type: type = str,
        memoryview_cast: str = '@c'
):
    from sys import (getsizeof)
    from itertools import (chain, repeat)
    from ctypes import (memset, cast, POINTER, c_char)
    TRAILING = 1
    LEADING = getsizeof(str()) - TRAILING
    while True:
        if not len(search_string):
            break
        try:
            for offset, character in (
                    zip(
                        range(
                            string.index(search_string),
                            len(string)
                        ),
                        map(
                            ord,
                            chain(
                                replace_string,
                                repeat(
                                    terminate_char,
                                    len(search_string) - len(replace_string)
                                )
                            )
                        )
                    )
            ):
                memset(
                    id(string) + LEADING + offset,
                    character,
                    1
                )
        except ValueError:
            break
        if not global_replace:
            break
    if return_type is str:
        return string
    elif return_type is memoryview:
        return memoryview(
            cast(
                id(string) + LEADING,
                POINTER(
                    c_char * (sys.getsizeof(string) - LEADING - TRAILING)
                )
            )[0]
        ).cast(memoryview_cast)

Pretty sure this only works with CPython, of course...