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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def set_draw_color(self, r,g=-1,b=-1):
        "Set color for all stroking operations"
        if((r==0 and g==0 and b==0) or g==-1):
            self.draw_color=sprintf('%.3f G',r/255.0)
        else:
            self.draw_color=sprintf('%.3f %.3f %.3f RG',r/255.0,g/255.0,b/255.0)
        if(self.page>0):
            self._out(self.draw_color)