How do I change the USB mode with a keyboard? How do I change the USB mode and select an option such as MTP, PTP, MIDI or charging with only a keyboard?

My screen is broken and I am trying to change the USB mode blindly using a keyboard?

What keys do I need to press to select a USB mode?

I will post a picture showing the USB mode pop up that shows when you press the "USB for charging" notification here:
The solution to this problem is to instead open the Settings app and then click on Developer options, make sure you enable Developer Options at the top by pressing Enter on the Keyboard, once that is done scroll down the list with the down arrow and select and click "Select USB Configuration", after selecting that a pop up window will appear where the user only needs to select the desired USB mode they want by pressing the up or down arrow keys and then Enter on the keyboard. This will create a connection with your computer for the desired USB mode. 

A Helpful Tip: You might want to enable Google Talkback in the Accessibility settings to give spoken feedback on what is being selected by your keyboard on the screen. Accessibility is located in the settings app. Talkback helped me throughout this process since I was navigating my phone blindly (without being able to see what was on my screen, since it was broken). Talkback helps to mitigate navigating your phone blindly to a certain degree if you have a broken screen that doesn't display properly or at all.