'Index check'

def test10_checkindex(self):

    (pl, ul) = self.lists_of_len()
    for i in self.limits_plus(0):
        if (i < 0):
            self.assertEqual(ul._checkindex(i), (i + self.limit), '_checkindex(neg    index)')
        else:
            self.assertEqual(ul._checkindex(i), i, '_checkindex(pos    index)')
    for i in (((- self.limit) - 1), self.limit):
        self.assertRaises(IndexError, ul._checkindex, i)
    ul._IndexError = TypeError
    self.assertRaises(TypeError, ul._checkindex, ((- self.limit) - 1))
