Another python 2 fix and add docs

metakernel/pexpect.py

@@ -14,6 +14,12 @@
 def spawn(command, args=[], timeout=30, maxread=2000,
           searchwindowsize=None, logfile=None, cwd=None, env=None,
           ignore_sighup=True, echo=True, encoding='utf-8', **kwargs):
+    '''This is the main entry point for Pexpect. Use this functio to start
+    and control child applications.
+
+    See https://github.com/pexpect/pexpect/blob/master/pexpect/pty_spawn.py
+    for more information.
+    '''
     codec_errors = kwargs.get('codec_errors', kwargs.get('errors', 'strict'))
     if pty is None:
         if args:

metakernel/tests/test_expect.py

@@ -86,7 +86,7 @@ def test_expect_exact (self):
                 ).replace('\r', '\n').replace('\n\n', '\n').rstrip()
         assert the_old_way == the_new_way, hex_diff(the_old_way, the_new_way)
         p = pexpect.spawn('echo hello.?world')
-        i = p.expect_exact('.?')
+        i = p.expect_exact(u'.?')
         self.assertEqual(p.before, 'hello')
         self.assertEqual(p.after, '.?')