Trying to understand more in Python calls and Files/Classes

# Okay, I will try to explain this well enough...with what knowledge I have currently.

# First, I have a MotorBridge.py file. The file consists of line 227 of this file: https://github.com/silver2row/bbg/blob/master/MBC/MotorBridge.py which later entails some ideas on functions related to Stepper Motors.

# I know it is a class with functions in it, e.g. class MotorBridgeCape:

# I also know about the file that follows:


# Mr. Li from Seeed Studio in '15.

import MotorBridge
import time

def StepperMotorATest(): # This function is just made up?
    print ('Hello From MotorBridge')
    motor.StepperMotorAInit() # This is the init function from the MotorBridge.py file/MotorBridgeCape class.
    motor.StepperMotorAMove(1000, 1000) # This is the CW or CCW function
    time.sleep(1)
    motor.StepperMotorAMove(-1000, 1000)
    time.sleep(1)

#def StepperMotorBTest():
    #print ('Hello From MotorBridge')
    #motor.StepperMotorBInit()
    #motor.StepperMotorBMove(1000, 1000)
    #time.sleep(1)
    #motor.StepperMotorBMove(-1000, 1000)
    #time.sleep(1)


if __name__=="__main__":
    motor = MotorBridge.MotorBridgeCape() # Is this the only reason that motor.StepperMotorAInit() and motor.StepperMotorAMove() exist?
                                          # I mean...b/c of me making the motor definition equal the file.class()?
                                          # For instance, "WHATEVER = MyPyFile.MyClassFromMyPyFile() is why that above source works?
    while True:
        StepperMotorATest()
        #StepperMotorBTest()