A blonde get pulled over by a blonde cop.

"Can I see your drivers licence?"

"What's that" the blonde replies.

"It's a little card that has your picture on it."

The blonde searches through her purse and finds a little mirror, looks at it and says "this must be it" and hands it to the blonde cop.

The blonde cop looks at it and says "Oh. I'm sorry! I didn't know you were a cop too."