How do you remove a broken oil dipstick

The tube that the dip stick goes into is pressed into the block if you can manage to get that tube out by wiggling and pulling and wording back and forth you should be able to retrieve the other part of the dip stick
replace the tube by tapping on it gently ,it has a flange on the tube to where it suppose to go back down in the block to it will stop there and feel solid when you tap it , insuring you have it in far enough to get the correct oil reading

This has happened 2 times on my wife's 2000 Nissan Sentra and must bea bad design with location of the dipstick. I have driven and worked on cars for years and have never ran across this. Thegarage both times had to take off the oil pan and reach it from under the car. the dip stick was too far down and too narrow to reach it from the top.

I see you have two great answers already 1 I'll share what I know has and can work. Ofcourse (OR NOT!) The tool we keep close by is about 18 to 24 " lng. you stick the tip into the tube then squeeze the button and it opens a bit an if it is not to far down in the pan it will grip it as you release the button on the retriever ! Also we have a skinny magnet you may try to slip in the tube ! If the gauge part has fallen into the oil pan the magnet may work after you remove the tube / as some one has said you can do. Here's to getting it out ! dub