Blonde on blonde

A blonde woman was speeding down the road in her little red sports car and was pulled over by a woman police officer, who was also a blonde. The cop asked to see the blonde's driver's license. She dug through her purse and was getting progressively more agitated. "What does it look like?" she finally asked. The policewoman replied, "It's square and it has your picture on it." The driver finally found a square mirror, looked at it and handed it to the policewoman. "Here it is," she said. The blonde officer looked at the mirror, then handed it back saying, "Okay, you can go. I didn't realize you were a cop."