doc: add compound feature serialization

maint: pin siibra-python version

docs/develop.example.adding_serialization.md

@@ -0,0 +1,60 @@
+siibra v0.5 introduced compound features. New serialization strategies and models need to be introduced in order to take full advantage of the introduction of compound features.
+
+## Import the new class
+
+`api.serialization.util.siibra` Serves as the one and single entrypoint to siibra package. To access the new class `CompoundFeature`, import it here.
+
+```python
+# in api.serialization.util.siibra
+
+# ... trimmed for brevity
+
+from siibra.feature.feature import CompoundFeature
+```
+
+## Adding serialization model
+
+Next, we define the shape of serialized instances of `CompoundFeature`.
+
+Since `CompoundFeature` subclasses `Feature`, it is quite natural to have the model, `CompoundFeatureModel`, subclass `FeatureModel`. 
+
+Here, we also added the property `subfeature_keys`, which is the additional property of `CompoundFeatureModel` compared to `FeatureModel` see [more detail](../api.models/#api.models._commons.ConfigBaseModel.__init_subclass__)
+
+```python
+# in api.models.features._basetypes.feature
+
+# ... trimmed for brevity
+
+class CompoundFeatureModel(_FeatureModel, type="compound_feature"):
+    """CompoundFeatureModel"""
+    subfeature_keys: List[str]
+
+```
+
+## Adding serialization strategy
+
+We then add the logic of serialization.
+
+```python
+# in api.serialization.features.feature
+
+from api.serialization.util.siibra import CompoundFeature
+from api.models.features._basetypes.feature import CompoundFeatureModel
+
+from api.serialization.util import (
+    serialize,
+    instance_to_model
+)
+
+@serialize(CompoundFeature, pass_super_model=True)
+def serialize_cf(cf: CompoundFeature, detail=False, super_model_dict={}, **kwargs) -> CompoundFeatureModel:
+    return CompoundFeatureModel(
+        **super_model_dict,
+        subfeature_keys=cf.subfeature_keys
+    )
+
+```
+
+## Testing the added feature
+
+[start the developer server](./develop.md), and try to fetch a new feature.

mkdocs.yml

@@ -57,7 +57,9 @@ nav:
     - 'overview': 'architecture.overview.md'
     - 'architecture: caching': 'architecture.caching.md'
     - 'architecture: throughput': 'architecture.throughput.md'
-  - develop: 'develop.md'
+  - develop:
+    - 'start developer server': 'develop.md'
+    - 'example: adding CompoundFeature serialization': 'develop.example.adding_serialization.md'
   - api references:
     - api.siibra_api_config: 'api.siibra_api_config.md'
     - api.server: 'api.server.md'

requirements/siibra.txt

@@ -1,2 +1,2 @@
-siibra>=0.4a68
+siibra==0.4a68
 plotly