Python: match a long string with special characters and white spaces and then prepend two characters to the beginning

Question

I'm not sure how to approach this, i'm trying to match this long string in a text file that has lots of whitespace and special characters and append the characters to the front ie. "//"

i need to match this line:

$menu_items['gojo_project']                    => array('http://www.gojo.net/community/plugin-inventory/ops-gojo/gojo', 'gojo',3),

and turn it into this:

//$menu_items['gojo_project']                    => array('http://www.gojo.net/community/plugin-inventory/ops-gojo/gojo', 'gojo',3),

notice i just prepended two '/' character.

I tried using re.escape to format the string, but its just really long and still throw sytax error. Am i going about this the right way using 're' ? or is there a better pythonic way to match a string like this one in a text file and prepend to it?

Edit: Forgot to mention that i need to edit the file in-line. In short, its a long php script that i'm trying to find that line and comment it out (ie. //). So, I cant really use some of the proposed solutions(i think) since they have it writing the modification to a separate file.