How do I make it so that I can detect if two turtles are touching in Python Turtle? Is there a specific line of code that I could use?

I need to be able to make it so that the two turtles "a " and "i" have a collision detection that detects when they touch. Could someone please tell me what lines of code I need to add? I just started to lean python all I know is the basics. If Then Loops, Lists, Strings, Floats, Making funcions, user input, print function. I also just know the basics of the turtle module. I learned key inputs and moving the turtle.