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## 5.18.2

**`(fix):`** Preserve leading and trailing underscores in generated namespace/module names.
Previously a subpackage named `_agents` (via `x-fern-sdk-group-name: _agents`)
was transformed to `agents`, stripping the underscore. Now it generates a
private `_agents/` Python module with a matching `client._agents` accessor,
enabling the pattern of hiding autogenerated clients behind a hand-written
public layer.

This is scoped to namespace/module names only. Parameter, field, and property
casing is unchanged, so existing SDK method signatures are unaffected.

Note: if you already use a group name that begins or ends with an underscore
(e.g. `x-fern-sdk-group-name: _agents`), the generated module and accessor now
preserve that underscore (`_agents/` and `client._agents`) instead of stripping
it (`agents/` / `client.agents`). Regenerating will change those import paths.