def temporarySibling(self, extension=b""):
        """
        Construct a path referring to a sibling of this path.

        The resulting path will be unpredictable, so that other subprocesses
        should neither accidentally attempt to refer to the same path before it
        is created, nor they should other processes be able to guess its name
        in advance.

        @param extension: A suffix to append to the created filename.  (Note
            that if you want an extension with a '.' you must include the '.'
            yourself.)
        @type extension: L{bytes} or L{unicode}

        @return: a path object with the given extension suffix, C{alwaysCreate}
            set to True.
        @rtype: L{FilePath} with a mode equal to the type of C{extension}
        """
        ourPath = self._getPathAsSameTypeAs(extension)
        sib = self.sibling(_secureEnoughString(ourPath) +
                           self.clonePath(ourPath).basename() + extension)
        sib.requireCreate()
        return sib

        Construct a path referring to a sibling of this path.

        The resulting path will be unpredictable, so that other subprocesses
        should neither accidentally attempt to refer to the same path before it
        is created, nor they should other processes be able to guess its name
        in advance.

        @param extension: A suffix to append to the created filename.  (Note
            that if you want an extension with a '.' you must include the '.'
            yourself.)
        @type extension: L{bytes} or L{unicode}

        @return: a path object with the given extension suffix, C{alwaysCreate}
            set to True.
        @rtype: L{FilePath} with a mode equal to the type of C{extension}
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/python/filepath.py