diff --git a/mapytex/calculus/API/__init__.py b/mapytex/calculus/API/__init__.py
index 1b31d7d..7b77ce3 100644
--- a/mapytex/calculus/API/__init__.py
+++ b/mapytex/calculus/API/__init__.py
@@ -93,6 +93,19 @@ x^7
 5 + 2x^2 + (3 + 5) * x
 5 + 2x^2 + 8x
 
+>>> e = Expression.from_str("(2x+3)^2")
+>>> e_simplified = e.simplify()
+>>> e_simplified
+<Quadratic 12x + 4x^2 + 9>
+>>> for s in e_simplified.explain():
+...    print(s)
+(2x + 3)^2
+(2x + 3)(2x + 3)
+2x * 2x + 2x * 3 + 3 * 2x + 3 * 3
+2 * 2 * x^(1 + 1) + 3 * 2 * x + 3 * 2 * x + 9
+6x + 6x + 4x^2 + 9
+(6 + 6) * x + 4x^2 + 9
+12x + 4x^2 + 9
 
 """
 
diff --git a/mapytex/calculus/API/expression.py b/mapytex/calculus/API/expression.py
index 315b303..722d414 100644
--- a/mapytex/calculus/API/expression.py
+++ b/mapytex/calculus/API/expression.py
@@ -198,10 +198,10 @@ class Expression(object):
         
         :example:
         >>> e = Expression.from_str("2x", typing=False)
-        >>> print(e._tree.map_on_leaf(type))
+        >>> print(e._tree.map_on_leaf(lambda x: type(x).__name__))
         *
-         > <class 'mapytex.calculus.core.MO.mo.MOnumber'>
-         > <class 'mapytex.calculus.core.MO.mo.MOstr'>
+         > MOnumber
+         > MOstr
         >>> typed_e = e._typing()
         >>> print(type(typed_e._tree))
         <class 'mapytex.calculus.core.MO.monomial.MOMonomial'>
@@ -210,21 +210,28 @@ class Expression(object):
         <class 'mapytex.calculus.core.MO.monomial.MOMonomial'>
 
         >>> e = Expression.from_str("2x+3+4/5", typing=False)
-        >>> print(e._tree.map_on_leaf(type))
+        >>> print(e._tree.map_on_leaf(lambda x: type(x).__name__))
         +
          > +
          | > *
-         | | > <class 'mapytex.calculus.core.MO.mo.MOnumber'>
-         | | > <class 'mapytex.calculus.core.MO.mo.MOstr'>
-         | > <class 'mapytex.calculus.core.MO.mo.MOnumber'>
+         | | > MOnumber
+         | | > MOstr
+         | > MOnumber
          > /
-         | > <class 'mapytex.calculus.core.MO.mo.MOnumber'>
-         | > <class 'mapytex.calculus.core.MO.mo.MOnumber'>
+         | > MOnumber
+         | > MOnumber
+
         >>> typed_e = e._typing()
-        >>> print(typed_e._tree.map_on_leaf(type))
+        >>> print(e._tree.map_on_leaf(lambda x: type(x).__name__))
         +
-         > <class 'mapytex.calculus.core.MO.polynomial.MOpolynomial'>
-         > <class 'mapytex.calculus.core.MO.fraction.MOFraction'>
+         > +
+         | > *
+         | | > MOnumber
+         | | > MOstr
+         | > MOnumber
+         > /
+         | > MOnumber
+         | > MOnumber
         """
         try:
             return Expression(self._tree.apply(typing))
diff --git a/mapytex/calculus/API/renders.py b/mapytex/calculus/API/renders.py
index 7c87144..828206c 100644
--- a/mapytex/calculus/API/renders.py
+++ b/mapytex/calculus/API/renders.py
@@ -16,7 +16,7 @@ def _txt(mo_tree):
     """ txt render for MOs or Trees"""
     try:
         return tree2txt(mo_tree)
-    except AttributeError:
+    except ValueError:
         pass
 
     try:
@@ -28,7 +28,7 @@ def _tex(mo_tree):
     """ Tex render for MOs or Trees"""
     try:
         return tree2tex(mo_tree)
-    except AttributeError:
+    except ValueError:
         pass
 
     try:
diff --git a/mapytex/calculus/API/tokens/__init__.py b/mapytex/calculus/API/tokens/__init__.py
index d9a6b43..6876a8f 100644
--- a/mapytex/calculus/API/tokens/__init__.py
+++ b/mapytex/calculus/API/tokens/__init__.py
@@ -10,7 +10,7 @@
 Tokens represents MathObject at API level
 
 """
-from ...core.MO.mo import MO, MOnumber, MOstr
+from ...core.MO import MO, MOnumber, MOstr
 from ...core.MO.fraction import MOFraction
 from ...core.MO.monomial import MOstrPower, MOMonomial
 from ...core.MO.polynomial import MOpolynomial
diff --git a/mapytex/calculus/API/tokens/number.py b/mapytex/calculus/API/tokens/number.py
index 6cb497d..1c37949 100644
--- a/mapytex/calculus/API/tokens/number.py
+++ b/mapytex/calculus/API/tokens/number.py
@@ -11,8 +11,7 @@ Tokens representing interger and decimal
 
 """
 from .token import Token
-from ...core.MO import MO
-from ...core.MO.mo import MOnumber
+from ...core.MO import MO, MOnumber
 from ...core.MO.fraction import MOFraction
 from decimal import Decimal as _Decimal