From d2dffa8ff7f929b5948540fc2302d5f17e1aa8d8 Mon Sep 17 00:00:00 2001
From: lafrite <lafrite@poneyworld.net>
Date: Wed, 20 May 2015 18:49:51 +0200
Subject: [PATCH] solve a bug with par and ^

---
 pymath/operator.py | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/pymath/operator.py b/pymath/operator.py
index b643cad..df16a9f 100644
--- a/pymath/operator.py
+++ b/pymath/operator.py
@@ -570,6 +570,11 @@ class op(object):
             except AttributeError as e:
                 # op has not the attribute priority
                 pass
+            try:
+                if int(opl) < 0:
+                    ans = ["(", opl, ")"]
+            except ValueError:
+                pass
 
             ans = flatten_list([ans])
             if str_join: