$ tmp=`mktemp /tmp/foo.XXXXXXXXXX`; echo 'def foo: pass' > $tmp; python3 -m pdb $tmp; rm $tmp
Traceback (most recent call last):
  File "/usr/local/lib/python3.2/pdb.py", line 1556, in main
    pdb._runscript(mainpyfile)
  File "/usr/local/lib/python3.2/pdb.py", line 1437, in _runscript
    self.run(statement)
  File "/usr/local/lib/python3.2/bdb.py", line 392, in run
    exec(cmd, globals, locals)
  File "<string>", line 1, in <module>
  File "/tmp/foo.iLhPYHBZrF", line 1
    def foo: pass
           ^
SyntaxError: invalid syntax
Uncaught exception. Entering post mortem debugging
Running 'cont' or 'step' will restart the program
> <string>(1)<module>()
(Pdb) quit
Post mortem debugger finished. The /tmp/foo.iLhPYHBZrF will be restarted
Traceback (most recent call last):
  File "/usr/local/lib/python3.2/pdb.py", line 1556, in main
    pdb._runscript(mainpyfile)
  File "/usr/local/lib/python3.2/pdb.py", line 1437, in _runscript
    self.run(statement)
  File "/usr/local/lib/python3.2/bdb.py", line 392, in run
    exec(cmd, globals, locals)
  File "<string>", line 1, in <module>
  File "/tmp/foo.iLhPYHBZrF", line 1
    def foo: pass
           ^
SyntaxError: invalid syntax
Uncaught exception. Entering post mortem debugging
Running 'cont' or 'step' will restart the program
> <string>(1)<module>()
(Pdb) --KeyboardInterrupt--
(Pdb)