Merge pull request #28 from neutrinoceros/keyerror_explicit

Insightful KeyErrors

benedict/core/move.py

@@ -5,5 +5,7 @@ def move(d, key_src, key_dest, overwrite=True):
     if key_dest == key_src:
         return
     if key_dest in d and not overwrite:
-        raise KeyError
+        raise KeyError(
+            "'{}' already in target dict and `overwrite` is disabled.".format(key_dest)
+        )
     d[key_dest] = d.pop(key_src)

benedict/dicts/keylist/keylist_dict.py

@@ -36,7 +36,7 @@ class KeylistDict(dict):
         elif type_util.is_list(parent):
             del parent[key]
             return
-        raise KeyError
+        raise KeyError(keys)
 
     def __getitem__(self, key):
         if type_util.is_list_or_tuple(key):
@@ -49,7 +49,7 @@ class KeylistDict(dict):
             return parent[key]
         elif type_util.is_list(parent):
             return parent[key]
-        raise KeyError
+        raise KeyError(keys)
 
     def __setitem__(self, key, value):
         if type_util.is_list_or_tuple(key):

benedict/dicts/keylist/keylist_util.py

@@ -16,7 +16,7 @@ def _get_item_key_and_value(item, key):
             return (index, item[index], )
     elif type_util.is_dict(item):
         return (key, item[key], )
-    raise KeyError
+    raise KeyError(key)
 
 
 def _get_or_new_item_value(item, key, subkey):