“This is a big day, and we’re here with gratitude and anticipation,” said Naseema Shafi, CEO of Whitman-Walker Health, addressing an audience of several hundred people at a ribbon-cutting for its brand new Southeast D.C. health center on Monday.Rows of chairs, with a rainbow-colored fan nestled on each seat, were spread across a lawn, dotted with wooden tables shaded by large umbrellas, facing the east side of the health care center.