- [ci skip] `regardless` is usually followed by `of` and not by `if .. or not`.

activemodel/lib/active_model/conversion.rb

@@ -40,8 +40,8 @@ def to_model
       self
     end
 
-    # Returns an Array of all key attributes if any is set, regardless if
-    # the object is persisted or not. Returns +nil+ if there are no key attributes.
+    # Returns an Array of all key attributes if any of the attributes is set, whether or not
+    # the object is persisted. Returns +nil+ if there are no key attributes.
     #
     #   class Person
     #     include ActiveModel::Conversion