Added a key_name utility function to use with to_dict() methods

stix/utils/__init__.py

@@ -109,10 +109,12 @@ def attr_name(name):
     Example:
         >>> attr_name("id")
         'id_'
-        >>> attr_name("title")
+        >>> attr_name("Title")
         'title
 
     """
+    name = name.lower()
+
     if name.startswith("_"):
         name = name[1:]
 
@@ -122,6 +124,19 @@ def attr_name(name):
     return name
 
 
+def key_name(name):
+    """Converts the input attribute name `name` into a key to be
+    used in `to_dict()` return dictionaries.
+
+    """
+    name = attr_name(name)
+
+    if name.endswith("_"):
+        return name[:-1]
+
+    return name
+
+
 def is_sequence(item):
     """Returns ``True`` if `value` is a sequence type (e.g., ``list``, or
     ``tuple``). String types will return ``False``.