Computer Science (Python) > computational-thinking-and-programming-2 > Data Structures

A stack named

contains records of some computer keyboards. Each record is represented as a list containing Make, Keys, Connectivity. The Make and Connectivity are strings, and Keys is an integer. For example, a record in the stack may be .

Write the following user-defined functions in Python to perform the specified operations on

: (I) : This function takes the stack KeyStack and a new record new_key as arguments and pushes this new record onto the stack. (II) : This function pops the topmost record from the stack and returns it. If the stack is already empty, the function should display the message "Underflow". (III) : This function checks whether the stack is empty. If the stack is empty, the function should return True, otherwise the function should return False.