diff --git a/pymath/expression.py b/pymath/expression.py
index e24359c..fa32f0a 100644
--- a/pymath/expression.py
+++ b/pymath/expression.py
@@ -123,9 +123,7 @@ class Expression(object):
         if len(steps[:-1]) > 0:
             self.steps += [flatten_list(s) for s in steps[:-1]]
 
-        print("self.steps -> ", self.steps)
         self.child = Expression(steps[-1])
-        print("self.child -> ", self.child)
 
     ## ---------------------
     ## String parsing
@@ -359,8 +357,7 @@ def test(exp):
     print("\n")
 
 if __name__ == '__main__':
-    #Expression.STR_RENDER = txt
-    Expression.STR_RENDER = lambda x: str(x)
+    Expression.STR_RENDER = txt
     exp = "2 ^ 3 * 5"
     test(exp)
 
diff --git a/pymath/render.py b/pymath/render.py
index 24c36e8..05fa577 100644
--- a/pymath/render.py
+++ b/pymath/render.py
@@ -3,6 +3,7 @@
 
 from .generic import Stack,flatten_list
 from .fraction import Fraction
+from .operator import Operator
 
 __all__ = ['Render']
 
@@ -195,7 +196,7 @@ class Render(object):
         :returns: boolean
 
         """
-        return (type(exp) == str and exp in self.operators)
+        return (type(exp) == Operator and str(exp) in self.operators)
 
 class flist(list):
     """Fake list- they are used to stock the main operation of an rendered expression"""
diff --git a/test/test_renders.py b/test/test_renders.py
index 8f0bec4..6453dff 100644
--- a/test/test_renders.py
+++ b/test/test_renders.py
@@ -6,6 +6,7 @@ import unittest
 
 from pymath.renders import tex, txt
 from pymath.fraction import Fraction
+from pymath.operator import Operator 
 
 
 
@@ -22,21 +23,21 @@ class TestTexRender(unittest.TestCase):
         self.assertEqual(tex([Fraction(1,2)]), "\\frac{ 1 }{ 2 }")
 
     def test_mult_interger(self):
-        exps = [ [2, 3, "*"], [2, -3, "*"], [-2, 3, "*"]]
+        exps = [ [2, 3, Operator("*", 2)], [2, -3, Operator("*", 2)], [-2, 3, Operator("*", 2)]]
         wanted_render = [ "2 \\times 3", "2 \\times ( -3 )", "-2 \\times 3"]
         for (i,e) in enumerate(exps):
             rend = tex(e)
             self.assertEqual(rend, wanted_render[i])
 
     def test_mult_letter(self):
-        exps = [ [2, "a", "*"], ["a", 3, "*"], [-2, "a", "*"], ["a", -2, "*"]]
+        exps = [ [2, "a", Operator("*", 2)], ["a", 3, Operator("*", 2)], [-2, "a", Operator("*", 2)], ["a", -2, Operator("*", 2)]]
         wanted_render = [ "2 a", "a \\times 3", "-2 a", "a \\times ( -2 )"]
         for (i,e) in enumerate(exps):
             rend = tex(e)
             self.assertEqual(rend, wanted_render[i])
 
     def test_mult_fraction(self):
-        exps = [ [2, Fraction(1,2), "*"], [Fraction(1,2), 3, "*"]]
+        exps = [ [2, Fraction(1,2), Operator("*", 2)], [Fraction(1,2), 3, Operator("*", 2)]]
         wanted_render = [ "2 \\times \\frac{ 1 }{ 2 }", "\\frac{ 1 }{ 2 } \\times 3"]
         for (i,e) in enumerate(exps):
             rend = tex(e)
@@ -64,21 +65,27 @@ class TesttxtRender(unittest.TestCase):
         self.assertEqual(txt([Fraction(1,2)]), "1 / 2")
 
     def test_mult_interger(self):
-        exps = [ [2, 3, "*"], [2, -3, "*"], [-2, 3, "*"]]
+        exps = [ [2, 3, Operator("*", 2)], \
+                [2, -3, Operator("*", 2)], \
+                [-2, 3, Operator("*", 2)]]
         wanted_render = [ "2 * 3", "2 * ( -3 )", "-2 * 3"]
         for (i,e) in enumerate(exps):
             rend = txt(e)
             self.assertEqual(rend, wanted_render[i])
 
     def test_mult_letter(self):
-        exps = [ [2, "a", "*"], ["a", 3, "*"], [-2, "a", "*"], ["a", -2, "*"]]
+        exps = [ [2, "a", Operator("*", 2)], \
+                ["a", 3, Operator("*", 2)], \
+                [-2, "a", Operator("*", 2)], \
+                ["a", -2, Operator("*", 2)]]
         wanted_render = [ "2 a", "a * 3", "-2 a", "a * ( -2 )"]
         for (i,e) in enumerate(exps):
             rend = txt(e)
             self.assertEqual(rend, wanted_render[i])
 
     def test_mult_fraction(self):
-        exps = [ [2, Fraction(1,2), "*"], [Fraction(1,2), 3, "*"]]
+        exps = [ [2, Fraction(1,2), Operator("*", 2)], \
+                [Fraction(1,2), 3, Operator("*", 2)]]
         wanted_render = [ "2 * 1 / 2", "1 / 2 * 3"]
         for (i,e) in enumerate(exps):
             rend = txt(e)