diff --git a/lark/__init__.py b/lark/__init__.py
index 83d03f8..fd5b28e 100644
--- a/lark/__init__.py
+++ b/lark/__init__.py
@@ -5,4 +5,4 @@ from .exceptions import ParseError, LexError, GrammarError, UnexpectedToken, Une
 from .lexer import Token
 from .lark import Lark
 
-__version__ = "0.6.5"
+__version__ = "0.6.6"
diff --git a/lark/load_grammar.py b/lark/load_grammar.py
index 15bc7e7..2e871f5 100644
--- a/lark/load_grammar.py
+++ b/lark/load_grammar.py
@@ -511,7 +511,7 @@ class Grammar:
 
                 empty_indices = [x==_EMPTY for i, x in enumerate(expansion)]
                 if any(empty_indices):
-                    exp_options = copy(options) or RuleOptions()
+                    exp_options = copy(options) if options else RuleOptions()
                     exp_options.empty_indices = empty_indices
                     expansion = [x for x in expansion if x!=_EMPTY]
                 else: