Implement toJsonDict for list types (siList, siHybrid).

src/AbstractListType.py

-from __future__ import annotations # for type annotation recursion
+from __future__ import annotations
+from collections import defaultdict # for type annotation recursion
 
 from AbstractQuantityTypeData import AbstractQuantityTypeData
 from AbstractValueType import AbstractValueType
@@ -10,6 +11,13 @@ class AbstractListType(AbstractQuantityTypeData):
         super().__init__()
         self.children = children
     
+    def toJsonDict(self):
+        result = defaultdict(list)
+        for child in self.children:
+            childJson = child.toJsonDict()
+            for key, value in childJson.items():
+                result[key].append(value)
+        return dict(result)
 
     def flatten(self):
         pass

src/SiHybrid.py

@@ -14,6 +14,9 @@ class SiHybrid(AbstractListType):
     def getUnits(self):
         pass
 
+    def toJsonDict(self):
+        return {'si:hybrid': super().toJsonDict()}
+
     def __repr__(self) -> str:
         params = {key: value for key, value in vars(self).items() if value is not None}
         paramStr = ", ".join(f"{key}={repr(value)}" for key, value in params.items())

src/SiList.py

@@ -16,6 +16,24 @@ class SiList(AbstractListType):
         super().__init__(children)
         self.label = label
         self.dateTime = dateTime
+
+    def toJsonDict(self):
+        keyMapping = {
+            'label': 'si:label',
+            'dateTime': 'si:dateTime',
+        }
+        attributes = super().toJsonDict() # converts all the data in 'children'
+        for key, value in self.__dict__.items():
+            if value:
+                if key in keyMapping:
+                    attributes[keyMapping[key]] = value
+                elif key == 'children':
+                    pass
+                else:
+                    attributes[key] = value
+                    # TODO: This should not happen, maybe add a warning?
+
+        return {'si:list': attributes}
     
     def __repr__(self) -> str:
         params = {key: value for key, value in vars(self).items() if value is not None}