'Append a run to this paragraph containing *text* and having character
style identified by style ID *style*. *text* can contain tab
(``\t``) characters, which are converted to the appropriate XML form
for a tab. *text* can also include newline (``\n``) or carriage
return (``\r``) characters, each of which is converted to a line
break.'

def add_run(self, text=None, style=None):

    r = self._p.add_r()
    run = Run(r, self)
    if text:
        run.text = text
    if style:
        run.style = style
    return run
