diff --git a/Nim-for-Python-Programmers.md b/Nim-for-Python-Programmers.md
index 8cc0fe2..9129c8e 100644
--- a/Nim-for-Python-Programmers.md
+++ b/Nim-for-Python-Programmers.md
@@ -29,7 +29,7 @@ Types                | Dynamic                            | Static
 Dependent types      | -                                | Partial support
 Generics             | Duck typing             | Yes
 int8/16/32/64 types  | No                   | Yes
-Bigints              | Yes (transparently)                  | Yes (via nimble package)
+Bigints (arbitrary size) | Yes (transparently)                  | Yes (via nimble package)
 Arrays               | Yes                               | Yes
 Bounds-checking      | Yes                                | Yes
 Type inference       | Duck typing               | Yes (extensive support)
@@ -107,8 +107,7 @@ That will return a compilation error, because the objects have different sizes.
 
 So, when using inheritance, be sure to inherit using refs, unless you know what you are doing. Also, check out Nim's generic programming capabilities as an alternative to OOP and inheritance.
 
-
-## Data structures
+## From Python to Nim
 
 ### Python tuples
 
@@ -124,3 +123,8 @@ The Nim set type is faster and memory-efficient.
 ### Dictionaries
 
 Use [HashSet](http://nim-lang.org/sets.html)
+
+### ABC
+
+See[this](http://rosettacode.org/wiki/Abstract_type#Nim)
+