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

@style.setter
def style(self, style):

    if (style is None):
        self._remove_rStyle()
    elif (self.rStyle is None):
        self._add_rStyle(val=style)
    else:
        self.rStyle.val = style
