code: def vertices(self):
          '''
          A dictionary of four points where the axes intersect the ellipse, dict.
          '''
          return {'a': self.a, 'a_neg': self.a_neg,
                  'b': self.b, 'b_neg': self.b_negf vertices(self):
          '''
          A dictionary of four points where the axes intersect the ellipse, dict.
          '''
          return {'a': self.a, 'a_neg': self.a_neg,
                  'b': self.b, 'b_neg': self.b_neg}
docs: A dictionary of four points where the axes intersect the ellipse, dict.