[Mohith26]

Closes #269

import dropbox imports every namespace module, because the generated base.py and base_team.py start with from dropbox import <namespace> for all 21 namespaces. Most of that is team_log (about 122k lines), which a typical app never touches.

This changes the generator to emit lazy references instead:

from dropbox._lazy_namespace import LazyNamespace

team_log = LazyNamespace("dropbox.team_log")

LazyNamespace imports the real module through importlib.import_module the first time an attribute is read, so route methods (which look up team_log.get_events etc. inside the method body) work unchanged, and concurrent first use is covered by the import lock. from dropbox import team_log still returns the real module.

Changes:

• generator/dropbox_python_client.stoneg.py: override _generate_imports
• generate_base_client.py: generate base_team with the same generator as base (it used stone's built-in python_client), so it gets lazy imports too. The only other difference in base_team.py is that the abstract request signature now includes extra_headers=None, matching base.py.
• dropbox/base.py, dropbox/base_team.py: regenerated with python generate_base_client.py, ruff format dropbox, ruff check --fix dropbox (same steps as spec_update.yml). Before my change, that pipeline reproduced the committed files exactly, so the diff is only the import block.
• scripts/benchmark_import.py: measures import dropbox in fresh interpreters, with requests and stone imported first

Numbers from python scripts/benchmark_import.py 21 (Apple Silicon arm64, Python 3.12, median of 21 runs; traced memory median of 3):

	before	after
import dropbox time	60.9 ms	23.4 ms
traced memory (tracemalloc)	22.5 MB	6.5 MB
RSS increase	30.8 MB	7.8 MB
dropbox.* modules loaded	30	24

team, team_log, account, check, contacts, openid and secondary_emails are no longer loaded at import. files, sharing, paper, riviera and file_requests still load at import because some route methods use their types as default argument values. The cost of a namespace isn't removed, just moved to the first call that needs it.

Tests (test/unit/test_lazy_namespace.py): a fresh interpreter doesn't load team/team_log on import dropbox; team_log_get_events loads it and passes the real route object and arg type to request; 16 threads hitting a cold namespace at once get the same module; proxy dir/repr/missing attribute/missing module behavior; a user route still builds real files types.

Checklist

General Contributing

• Have you read the Code of Conduct and signed the CLA?

Is This a Code Change?

• Non-code related change (markdown/git settings etc)
• SDK Code Change
• Example/Test Code Change

Validation

• Does tox pass? (I ran tox's commands directly: ruff check dropbox example test, ruff format --check dropbox example test, and the unit tests)
• Do the tests pass? (pytest test/unit/: 125 passed)

[CLAassistant]

All committers have signed the CLA.

[greg-db]

Thanks for submitting this! I'll ask the team to review it.