apple.py

def latest_iphone():
    return "iPhone 11 Pro"

google.py

import apple # just put the name of the file without .py extension

def search(str):
    if str == "What is the latest iPhone version":
        return apple.latest_iphone()
    ...

If you don't want to type name of the module every time you create an object or call a function, instead of import apple you can do:

from apple import *

this will make all the classes and functions from apple module available right away:

# instead of
apple.latest_iphone()
# you can just write
latest_iphone()

Imagine you have a class Tk in the module tkinter

You can get all the methods that class Tk has by using dir function:

dir(tkinter.Tk) # will return list of all class names

dir(tkinter) # will return list of all classes and functions in the module

Some classes have __doc__ property, so you can get more detailed documentation:

tkinter.Tk.__doc__ # Will return doc for Tk

Although sometimes documentation is not very useful:

tkinter.Tk.mainloop.__doc__ #'Call the mainloop of Tk.'