Append `a:r` and `a:br` elements to *p* based on *text*.

        Any `\n` characters in *text* delimit `a:r` (run) elements and
        themselves are translated to `a:br` (line-break) elements.

def append_text(self, text):
        """Append `a:r` and `a:br` elements to *p* based on *text*.

        Any `\n` characters in *text* delimit `a:r` (run) elements and
        themselves are translated to `a:br` (line-break) elements.
        """
        for idx, r_str in enumerate(text.split('\n')):
            # ---breaks are only added *between* items, not at start---
            if idx > 0:
                self.add_br()
            # ---runs that would be empty are not added---
            if r_str:
                self.add_r(r_str)