PHILADELPHIA, July 29, 2016 (Xinhua) -- Singer Katy Perry performs on the last day of the 2016 Democratic National Convention in Philadelphia, Pennsylvania, the United States, July 28, 2016. (Xinhua/Li Muzi/IANS)morePHILADELPHIA, July 29, 2016 (Xinhua) -- Singer Katy Perry performs on the last day of the 2016 Democratic National Convention in Philadelphia, Pennsylvania, the United States, July 28, 2016. (Xinhua/Li Muzi/IANS)morePHILADELPHIA, July 29, 2016 (Xinhua) -- Singer Katy Perry performs on the last day of the 2016 Democratic National Convention in Philadelphia, Pennsylvania, the United States, July 28, 2016. (Xinhua/Li Muzi/IANS)more