Drop the underscore prefix on the other local variable name.
diff --git a/OpenSSL/crypto.py b/OpenSSL/crypto.py
index 71862da..1d0f494 100644
--- a/OpenSSL/crypto.py
+++ b/OpenSSL/crypto.py
@@ -704,10 +704,10 @@
         :return: A list of X509Extension objects.
         """
         exts = []
-        _native_exts_obj = _lib.X509_REQ_get_extensions(self._req)
-        for i in range(0, _lib.sk_X509_EXTENSION_num(_native_exts_obj)):
+        native_exts_obj = _lib.X509_REQ_get_extensions(self._req)
+        for i in range(0, _lib.sk_X509_EXTENSION_num(native_exts_obj)):
             ext = X509Extension.__new__(X509Extension)
-            ext._extension = _lib.sk_X509_EXTENSION_value(_native_exts_obj, i)
+            ext._extension = _lib.sk_X509_EXTENSION_value(native_exts_obj, i)
             exts.append(ext)
         return exts