$co_author = Array
(
    [ID] => 91
    [user_firstname] => Brian
    [user_lastname] => Rutland
    [nickname] => brian.rutland
    [user_nicename] => brian-rutland
    [display_name] => Brian Rutland
    [user_email] => brian.rutland@accenture.com
    [user_url] => 
    [user_registered] => 2018-11-29 13:38:20
    [user_description] => 
    [user_avatar] => 
)

 $co_author = Array
(
    [ID] => 92
    [user_firstname] => Tom
    [user_lastname] => Skomba
    [nickname] => tom.skomba
    [user_nicename] => tom-skomba
    [display_name] => Tom Skomba
    [user_email] => tom.skomba@accenture.com
    [user_url] => 
    [user_registered] => 2018-12-04 20:07:11
    [user_description] => 
    [user_avatar] => 
)