python function call in other function

Question

so my question is that in my code actually on consists of two python module on the main and other the sub. In sub there is a function which I need to stop the working and return the control back to the next line of the main module. How can it be done. I tried exit() but it stops the execution. just for example

#module 1 -- ex2

import ex1
def add():
 print('before calling ex1')
 ex1.sub()
 print('after calling ex1')
add()

#module 2 -- ex1

def sub():
 print('inside sub')
 error()
 print('after error call')
def error():
 print('inside error')
 return #in place of this

so I want is that when my code enters the error function it will print the statement and the module 2 ends execution and the control will flow to the print('after calling ex1') this statement in module 1. Please help guys

note: please do not use multiple returns as example:

#module 2 -- ex1

def sub():
 print('inside sub')
 error()
 return # Please do not use
 print('after error call')
def error():
 print('inside error')
 return #in place of this

I need the output to be like ---

before calling ex1
inside sub
inside error
after calling ex1 

• Barmar: Use exceptions and try/except
• Barmar: Modules don't implement control flow, only functions do. A module is just a collection of functions/variables and a namespace.

Answer 1

This is what exception handling is designed for, with the raise statement and the try .. except construct in Python:

#module 1 -- ex2
import ex1
def add():
 print('before calling ex1')
 try:
 ex1.sub()
 except RuntimeError as e:
 print('An error occurred while calling ex1.sub:', str(e))
 # or just a pass statement if you do not want anything done about the error
 print('after calling ex1')
add()
#module 2 -- ex1
def sub():
 print('inside sub')
 error()
 print('after error call')
def error():
 print('inside error')
 raise RuntimeError('some error')

• Diogenis Siganos: This will technically print that an error occurred too, so perhaps you should replace that line with pass
• blhsing: @Bonfire Sure, added a note then.

Answer 2

Your error function must be a function that returns a value. True or False

def error():
 print('inside error')
 return True 
 # or return False
def sub():
 print('inside sub')
 if(error()):
 return
 print('after error call')