remove code specific to python2

IPython/core/tests/test_events.py

@@ -1,8 +1,5 b''
 import unittest
-try:  # Python 3.3 +
-    from unittest.mock import Mock
-except ImportError:
-    from mock import Mock
+from unittest.mock import Mock
 
 from IPython.core import events
 import IPython.testing.tools as tt

IPython/lib/latextools.py

@@ -9,6 +9,7 b' import os'
 import tempfile
 import shutil
 import subprocess
+from base64 import encodebytes
 
 from IPython.utils.process import find_cmd, FindCmdError
 from traitlets.config import get_config
@@ -16,11 +17,6 b' from traitlets.config.configurable import SingletonConfigurable'
 from traitlets import List, Bool, Unicode
 from IPython.utils.py3compat import cast_unicode, cast_unicode_py2 as u, PY3
 
-try: # Py3
-    from base64 import encodebytes
-except ImportError: # Py2
-    from base64 import encodestring as encodebytes
-
 
 class LaTeXTool(SingletonConfigurable):
     """An object to store configuration of the LaTeX tool."""

IPython/lib/tests/test_latextools.py

@@ -3,12 +3,7 b''
 
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
-
-try:
-    from unittest.mock import patch
-except ImportError:
-    from mock import patch
-
+from unittest.mock import patch
 import nose.tools as nt
 
 from IPython.lib import latextools