diff --git a/hgdemandimport/py3token.py b/hgdemandimport/py3token.py
--- a/hgdemandimport/py3token.py
+++ b/hgdemandimport/py3token.py
@@ -1,3 +1,58 @@
+# Vendored copy of Lib/token.py from cpython.
+
+# Copyright (c) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
+# 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018 Python Software Foundation; All
+# Rights Reserved
+#
+# PYTHON SOFTWARE FOUNDATION LICENSE VERSION 2
+# --------------------------------------------
+#
+# 1. This LICENSE AGREEMENT is between the Python Software Foundation
+# ("PSF"), and the Individual or Organization ("Licensee") accessing and
+# otherwise using this software ("Python") in source or binary form and
+# its associated documentation.
+#
+# 2. Subject to the terms and conditions of this License Agreement, PSF hereby
+# grants Licensee a nonexclusive, royalty-free, world-wide license to reproduce,
+# analyze, test, perform and/or display publicly, prepare derivative works,
+# distribute, and otherwise use Python alone or in any derivative version,
+# provided, however, that PSF's License Agreement and PSF's notice of copyright,
+# i.e., "Copyright (c) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009,
+# 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018 Python Software
+# Foundation; All Rights Reserved" are retained in Python alone or in any
+# derivative version prepared by Licensee.
+#
+# 3. In the event Licensee prepares a derivative work that is based on
+# or incorporates Python or any part thereof, and wants to make
+# the derivative work available to others as provided herein, then
+# Licensee hereby agrees to include in any such work a brief summary of
+# the changes made to Python.
+#
+# 4. PSF is making Python available to Licensee on an "AS IS"
+# basis.  PSF MAKES NO REPRESENTATIONS OR WARRANTIES, EXPRESS OR
+# IMPLIED.  BY WAY OF EXAMPLE, BUT NOT LIMITATION, PSF MAKES NO AND
+# DISCLAIMS ANY REPRESENTATION OR WARRANTY OF MERCHANTABILITY OR FITNESS
+# FOR ANY PARTICULAR PURPOSE OR THAT THE USE OF PYTHON WILL NOT
+# INFRINGE ANY THIRD PARTY RIGHTS.
+#
+# 5. PSF SHALL NOT BE LIABLE TO LICENSEE OR ANY OTHER USERS OF PYTHON
+# FOR ANY INCIDENTAL, SPECIAL, OR CONSEQUENTIAL DAMAGES OR LOSS AS
+# A RESULT OF MODIFYING, DISTRIBUTING, OR OTHERWISE USING PYTHON,
+# OR ANY DERIVATIVE THEREOF, EVEN IF ADVISED OF THE POSSIBILITY THEREOF.
+#
+# 6. This License Agreement will automatically terminate upon a material
+# breach of its terms and conditions.
+#
+# 7. Nothing in this License Agreement shall be deemed to create any
+# relationship of agency, partnership, or joint venture between PSF and
+# Licensee.  This License Agreement does not grant permission to use PSF
+# trademarks or trade name in a trademark sense to endorse or promote
+# products or services of Licensee, or any third party.
+#
+# 8. By copying, installing or otherwise using Python, Licensee
+# agrees to be bound by the terms and conditions of this License
+# Agreement.
+
 """Token constants (from "token.h")."""
 
 __all__ = ['tok_name', 'ISTERMINAL', 'ISNONTERMINAL', 'ISEOF']
diff --git a/hgdemandimport/py3tokenize.py b/hgdemandimport/py3tokenize.py
--- a/hgdemandimport/py3tokenize.py
+++ b/hgdemandimport/py3tokenize.py
@@ -1,3 +1,58 @@
+# Vendored copy of Lib/tokenize.py from cpython.
+
+# Copyright (c) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
+# 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018 Python Software Foundation; All
+# Rights Reserved
+#
+# PYTHON SOFTWARE FOUNDATION LICENSE VERSION 2
+# --------------------------------------------
+#
+# 1. This LICENSE AGREEMENT is between the Python Software Foundation
+# ("PSF"), and the Individual or Organization ("Licensee") accessing and
+# otherwise using this software ("Python") in source or binary form and
+# its associated documentation.
+#
+# 2. Subject to the terms and conditions of this License Agreement, PSF hereby
+# grants Licensee a nonexclusive, royalty-free, world-wide license to reproduce,
+# analyze, test, perform and/or display publicly, prepare derivative works,
+# distribute, and otherwise use Python alone or in any derivative version,
+# provided, however, that PSF's License Agreement and PSF's notice of copyright,
+# i.e., "Copyright (c) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009,
+# 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018 Python Software
+# Foundation; All Rights Reserved" are retained in Python alone or in any
+# derivative version prepared by Licensee.
+#
+# 3. In the event Licensee prepares a derivative work that is based on
+# or incorporates Python or any part thereof, and wants to make
+# the derivative work available to others as provided herein, then
+# Licensee hereby agrees to include in any such work a brief summary of
+# the changes made to Python.
+#
+# 4. PSF is making Python available to Licensee on an "AS IS"
+# basis.  PSF MAKES NO REPRESENTATIONS OR WARRANTIES, EXPRESS OR
+# IMPLIED.  BY WAY OF EXAMPLE, BUT NOT LIMITATION, PSF MAKES NO AND
+# DISCLAIMS ANY REPRESENTATION OR WARRANTY OF MERCHANTABILITY OR FITNESS
+# FOR ANY PARTICULAR PURPOSE OR THAT THE USE OF PYTHON WILL NOT
+# INFRINGE ANY THIRD PARTY RIGHTS.
+#
+# 5. PSF SHALL NOT BE LIABLE TO LICENSEE OR ANY OTHER USERS OF PYTHON
+# FOR ANY INCIDENTAL, SPECIAL, OR CONSEQUENTIAL DAMAGES OR LOSS AS
+# A RESULT OF MODIFYING, DISTRIBUTING, OR OTHERWISE USING PYTHON,
+# OR ANY DERIVATIVE THEREOF, EVEN IF ADVISED OF THE POSSIBILITY THEREOF.
+#
+# 6. This License Agreement will automatically terminate upon a material
+# breach of its terms and conditions.
+#
+# 7. Nothing in this License Agreement shall be deemed to create any
+# relationship of agency, partnership, or joint venture between PSF and
+# Licensee.  This License Agreement does not grant permission to use PSF
+# trademarks or trade name in a trademark sense to endorse or promote
+# products or services of Licensee, or any third party.
+#
+# 8. By copying, installing or otherwise using Python, Licensee
+# agrees to be bound by the terms and conditions of this License
+# Agreement.
+
 """Tokenization help for Python programs.
 
 tokenize(readline) is a generator that breaks a stream of bytes into