Once upon a time in the desert

Two Africans with their friend was in the middle of desert.
Meanwhile, an African person finds a magic lamp.
Then the giant comes and tells everybody to make a wish.

"Make me white" says the first African.
As he says this, the third person was laughing then the African says: What are you laughing at?
The third person said, "Nothing."

Then the giant said to the second African: What do you want?
"Make me white, too," said the African.
The third person laughs again.
An African said, "Why are you laughing?"
The third one said, "Nothing."
It's the third person turn. The giant asks him: What do you want?
The third person says: black them again.