There was a non-ascii character in the source. Replaced by a hex escape.
diff --git a/Lib/test/test_email.py b/Lib/test/test_email.py
index 7e38eda..5d6adc0 100644
--- a/Lib/test/test_email.py
+++ b/Lib/test/test_email.py
@@ -1457,7 +1457,7 @@
# Test the keep_eols flag
eq(he('hello\nworld', keep_eols=1), '=?iso-8859-1?q?hello=0Aworld?=')
# Test a non-ASCII character
- eq(he('helloÇthere'), '=?iso-8859-1?q?hello=C7there?=')
+ eq(he('hello\xc7there'), '=?iso-8859-1?q?hello=C7there?=')
# Test the maxlinelen argument
eq(he('xxxx ' * 20, maxlinelen=40), """\
=?iso-8859-1?q?xxxx_xxxx_xxxx_xxxx_xx?=