three.py

# sys_shelve_importer_create.py
import shelve
import os

filename = '/tmp/pymotw_import_example.shelve'
if os.path.exists(filename + '.db'):
    os.unlink(filename + '.db')
with shelve.open(filename) as db:
    db['data:README'] = b"""
==============
package README
==============

This is the README for ``package``.
"""
    db['package.__init__'] = b"""
print('package imported')
message = 'This message is in package.__init__'
"""
    db['package.module1'] = b"""
print('package.module1 imported')
message = 'This message is in package.module1'
"""
    db['package.subpackage.__init__'] = b"""
print('package.subpackage imported')
message = 'This message is in package.subpackage.__init__'
"""
    db['package.subpackage.module2'] = b"""
print('package.subpackage.module2 imported')
message = 'This message is in package.subpackage.module2'
"""
    db['package.with_error'] = b"""
print('package.with_error being imported')
raise ValueError('raising exception to break import')
"""
    print('Created {} with:'.format(filename))
    for key in sorted(db.keys()):
        print('  ', key)