Allow for overrides in deep_dict_merge

[hannes-ucsc]

Index: src/azul/collections.py
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/src/azul/collections.py b/src/azul/collections.py
--- a/src/azul/collections.py	(revision 3c97698e6421dd74eda0b9c2b031825ecdd51254)
+++ b/src/azul/collections.py	(date 1731976825362)
@@ -85,20 +85,27 @@
     {}
     """
 
-    def __new__(cls, *dicts: Mapping) -> dict:
-        return cls.from_iterable(dicts)
+    def __new__(cls, *dicts: Mapping, override: bool | None = None) -> dict:
+        return cls.from_iterable(dicts, override=override)
 
     @classmethod
-    def from_iterable(cls, dicts: Iterable[Mapping], /) -> dict:
+    def from_iterable(cls, dicts: Iterable[Mapping], /, override: bool | None = None) -> dict:
         merged = {}
         for m in dicts:
             for k, v2 in m.items():
                 v1 = merged.setdefault(k, v2)
                 if v1 != v2:
                     if isinstance(v1, Mapping) and isinstance(v2, Mapping):
-                        merged[k] = deep_dict_merge(v1, v2)
+                        merged[k] = deep_dict_merge(v1, v2, override=override)
                     else:
-                        raise ValueError(f'{v1!r} != {v2!r}')
+                        if override is True:
+                            merged[k] = v2
+                        elif override is False:
+                            pass
+                        elif override is None:
+                            raise ValueError(f'{v1!r} != {v2!r}')
+                        else:
+                            raise ValueError('Expected boolean or None', override)
         return merged
 
 

Needs doctests and doc updates.

Also consider eliminating dict_merge and replacing the sole call site with one to deep_dict_merge. Lastly, consider renaming deep_dict_merge to dict_merge.