def __repr__(self):
        return "<Requirement(package={package}, version='{version}')>".format(
            package=self.package, version=self.version)
def dec_r(self, ind):
        r, c = self.row_col(ind)
        r -= 1
        if r < 0:
            r = self.nr - 1
        if r == (self.nr - 1) and c == (self.nc - 1):
            r = self.nr - 2
        return self.indx(r, c)