[No is also an answer!]
“Give me an unbreakable vow that you will help Draco finish the job assigned to him by dark lord”, says Narcissa Malfoy.
Snape looks into the darkness of Whatever Street and says, “There are very few people in this world, for whom I would do anything, and you lost that right, when you walked away on me 19 years, 2 months, and 10 hours back.”
He looks at Narcissa’s face for one last time and walks away, without saying any further word. Narcissa stands there alone, watches him disappear into the dark alleys, his flowing robes slowly following him, and images from past flashing before her eyes….
“Professor Langdon, we found this symbol inscribed…”
“Excuse me, hold on, How many times should I tell you that I am not this Langdon dude!”
“Professor, this is no time to joke, if we don’t act now, the whole world is going to end in 10 hrs…”
“..and how much of those 10 hrs do you want to waste on me. I am not a Professor, my last name is not Langdon, and all these symbols are just cave drawings to me.”
“What about your ID, which says Dr. Robert Langdon”
“Ohhh!! That!!! I was at this restaurant the other day, and I met this totallyyy drunk bastard, and he said that he was ready to trade his wallet for the piece of paper on which I was playing Pictionary. So, I just said deal, and here am I.”