class Student:def __init__(self, std):self.count = stddef print_std(self):for i in range(self.count):print(i)return
if __name__ == '__main__':Student(5).print_std()

$ python3
Python 3.6.7 |Anaconda, Inc.| (default, Oct 23 2018, 19:16:44)
[GCC 7.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import pdb_example
>>> import pdb
>>> pdb.run('pdb_example.Student(5).print_std()')
> <string>(1)<module>()
(Pdb)
EOF        b          cl         cont       disable    exit       interact   list       next       quit       retval     source     unalias    up
a          break      clear      continue   display    h          j          ll         p          r          run        step       undisplay  w
alias      bt         commands   d          down       help       jump       longlist   pp         restart    rv         tbreak     unt        whatis
args       c          condition  debug      enable     ignore     l          n          q          return     s          u          until      where
(Pdb) continue
0
1
2
3
4

$ python3 -m pdb pdb_example.py
> /home/andrew/code/meil/code/Mastering-Python-Scripting-for-System-Administrators-/Chapter02/pdb_example.py(1)<module>()
-> class Student:
(Pdb) continue
0
1
2
3
4
The program finished and will be restarted

$ python3 pdb_example.py
> /home/andrew/code/meil/code/Mastering-Python-Scripting-for-System-Administrators-/Chapter02/pdb_example.py(10)print_std()
-> print(i)
(Pdb) continue
0
> /home/andrew/code/meil/code/Mastering-Python-Scripting-for-System-Administrators-/Chapter02/pdb_example.py(9)print_std()
-> pdb.set_trace()
(Pdb) continue
1
> /home/andrew/code/meil/code/Mastering-Python-Scripting-for-System-Administrators-/Chapter02/pdb_example.py(10)print_std()
-> print(i)
(Pdb) continue
2
...