def is_path_sibling_creatable(pathname: str) -> bool:
    """Checks whether current user can create siblings of the given path.

    Returns
    -------
    `True` if the current user has sufficient permissions to create siblings
    (i.e., arbitrary files in the parent directory) of the passed pathname;
    `False` otherwise.
    """
    # Parent directory of the passed path. If empty, we substitute the current
    # working directory (CWD) instead.
    dirname = os.path.dirname(pathname) or os.getcwd()

    try:
        # For safety, explicitly close and hence delete this temporary file
        # immediately after creating it in the passed path's parent directory.
        with tempfile.TemporaryFile(dir=dirname):
            pass
        return True
    # While the exact type of exception raised by the above function depends on
    # the current version of the Python interpreter, all such types subclass
    # the following exception superclass.
    except EnvironmentError:
        return False
Checks whether current user can create siblings of the given path.

    Returns
    -------
    `True` if the current user has sufficient permissions to create siblings
    (i.e., arbitrary files in the parent directory) of the passed pathname;
    `False` otherwise.