The simplest and most straightforward way to run a debugger is from a command line. Our program will act as input to the debugger. You can use the debugger from command line as follows:

$ python3 -m pdb pdb_example.py

When you run the debugger from the command line, source code will be loaded and it will stop the execution on the first line it finds. Enter continue to continue the debugging. Here's the output:

student@ubuntu:~$ python3 -m pdb pdb_example.py
> /home/student/pdb_example.py(1)<module>()
-> class Student:
(Pdb) continue
0
1
2
3
4
The program finished and will be restarted
> /home/student/pdb_example.py(1)<module>()
-> class Student:
(Pdb)