Merge pull request #158 from viggo-devries/bugfix/context-reassign

This fixes a bug where context is reassigned if you pass an empty con…

Author: timsavage

src/odin/mapping/__init__.py

@@ -515,7 +515,9 @@ def apply(
             specified is returned.
 
         """
-        context = context or {}
+        if context is None:
+            context = {}
+
         mapping_result = mapping_result or cls.default_mapping_result
         context.setdefault("_loop_idx", [])