def set_dash_capstyle(self, s):
s = s.lower()<EOL>if s not in self.validCap:<EOL><INDENT>raise ValueError('<STR_LIT>' % (s,)<EOL>+ '<STR_LIT>' % (self.validCap,))<EOL><DEDENT>self._dashcapstyle = s<EOL>
Set the cap style for dashed linestyles

ACCEPTS: ['butt' | 'round' | 'projecting']