bpo-32178: Fix IndexError trying to parse 'To' header starting with ':'. (GH-15044)


This should fix the IndexError trying to retrieve `DisplayName.display_name` and `DisplayName.value` when the `value` is basically an empty string.

https://bugs.python.org/issue32178
(cherry picked from commit 09a1872a8007048dcdf825a476816c5e3498b8f8)

Co-authored-by: Abhilash Raj <maxking@users.noreply.github.com>
3 files changed