Two "easy" ways to get tracebacks which contain useless importlib._bootstrap rows:
- When there is a syntax error in the imported module
- On "import package.module", when top-level package cannot be imported


$ ./python -c "import foo"
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "<frozen importlib._bootstrap>", line 1421, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1388, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 527, in _check_name_wrapper
  File "<frozen importlib._bootstrap>", line 899, in load_module
  File "<frozen importlib._bootstrap>", line 880, in load_module
  File "<frozen importlib._bootstrap>", line 503, in module_for_loader_wrapper
  File "<frozen importlib._bootstrap>", line 744, in _load_module
  File "<frozen importlib._bootstrap>", line 857, in get_code
  File "./foo.py", line 1
    invalid syntax
                 ^
SyntaxError: invalid syntax


$ ./python
Python 3.3.0b1 (default:afdb0e1a9dac+, Jul 19 2012, 23:55:02) 
[GCC 4.4.3] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import _sqlite3
>>> del _sqlite3.register_converter
>>> import sqlite3.dump
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<frozen importlib._bootstrap>", line 1421, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1372, in _find_and_load_unlocked
  File "/home/amauryfa/python/cpython3.x/Lib/sqlite3/__init__.py", line 23, in <module>
    from sqlite3.dbapi2 import *
  File "/home/amauryfa/python/cpython3.x/Lib/sqlite3/dbapi2.py", line 83, in <module>
    register_adapters_and_converters()
  File "/home/amauryfa/python/cpython3.x/Lib/sqlite3/dbapi2.py", line 80, in register_adapters_and_converters
    register_converter("date", convert_date)
NameError: global name 'register_converter' is not defined