Remove builtin exceptions brackets

Author: dflook

docs/source/transforms/remove_exception_brackets.rst

@@ -4,6 +4,7 @@ Remove Builtin Exception Brackets
 This transform removes parentheses when raising builtin exceptions with no arguments.
 
 The raise statement automatically instantiates exceptions with no arguments, so the parentheses are unnecessary.
+This transform does nothing on Python 2.
 
 This transform is enabled by default. Disable by passing the ``remove_builtin_exception_brackets=False`` argument to the :func:`python_minifier.minify` function,
 or passing ``--no-remove-builtin-exception-brackets`` to the pyminify command.

src/python_minifier/transforms/remove_exception_brackets.py

@@ -9,6 +9,7 @@
 """
 
 import ast
+import sys
 
 from python_minifier.rename.binding import BuiltinBinding
 
@@ -116,6 +117,9 @@ def _remove_empty_call(binding):
 def remove_no_arg_exception_call(module):
     assert isinstance(module, ast.Module)
 
+    if sys.version_info < (3, 0):
+        return module
+
     for binding in module.bindings:
         if isinstance(binding, BuiltinBinding) and binding.name in builtin_exceptions:
             # We can remove any calls to builtin exceptions