Fix the compatibility docstring

test/test_utils.py

@@ -2,11 +2,10 @@ try:
     import readline
 except ImportError:
     readline = False
+import unittest
 
 from jedi import utils
 
-from .helpers import unittest
-
 
 @unittest.skipIf(not readline, "readline not found")
 class TestSetupReadline(unittest.TestCase):