Set val attribute of <w:pStyle> child element to *style*, adding a
        new element if necessary. If *style* is |None|, remove the <w:pStyle>
        element if present.

def style(self, style):
        """
        Set val attribute of <w:pStyle> child element to *style*, adding a
        new element if necessary. If *style* is |None|, remove the <w:pStyle>
        element if present.
        """
        if style is None:
            self._remove_pStyle()
            return
        pStyle = self.get_or_add_pStyle()
        pStyle.val = style