'Attempt to return a path with my name, given the extension at C{ext}.
@param ext: File-extension to search for.
@type ext: L{bytes} or L{unicode}
@return: The sibling path.
@rtype: L{FilePath} with the same mode as the type of C{ext}.'

def siblingExtension(self, ext):

    ourPath = self._getPathAsSameTypeAs(ext)
    return self.clonePath((ourPath + ext))
