diff --git a/source/Collection_Data_Types.rst b/source/Collection_Data_Types.rst
index 967456f1c75d6bc52a60147d1ce5d329c3252fb3..23b8a77879608f9e2e5b1905289d323499a670e8 100644
--- a/source/Collection_Data_Types.rst
+++ b/source/Collection_Data_Types.rst
@@ -424,7 +424,7 @@ pseudocode:
 |        *concatenate nt complement to rev_comp*
 |     *return rev_comp*
 
-.. literalinclude:: _static/code/rev_comp2.py
+.. literalinclude:: _static/code/rev_comp.py
    :linenos:
    :language: python
 
diff --git a/source/_static/code/rev_comp2.py b/source/_static/code/rev_comp2.py
index 59ea1a1e6157c645d808fbf58376e8a04f827900..92b634851390306718e66c93f98613f691f3646a 100644
--- a/source/_static/code/rev_comp2.py
+++ b/source/_static/code/rev_comp2.py
@@ -5,13 +5,9 @@ def rev_comp(seq):
     return the reverse complement of seq
     the case is respect but if the sequence mix upper and lower case the function will failed
     """
-    upper = seq.isupper()
     reverse = seq[::-1]
-    direct = 'acgt'
-    comp = 'tgca'
-    if upper:
-        table = string.maketrans(direct.upper(), comp.upper())
-    else:
-        table = string.maketrans(direct, comp)
+    direct = 'acgtATCG'
+    comp = 'tgcaTGCA'
+    table = string.maketrans(direct, comp)
     rev_comp = reverse.translate(table)
     return rev_comp
\ No newline at end of file