diff --git a/source/Data_Types.rst b/source/Data_Types.rst
index 65de161c593407ac7d408e06fe80f9de63671b94..100eee458510c24c876d6bcfbc091a59253eb3b6 100644
--- a/source/Data_Types.rst
+++ b/source/Data_Types.rst
@@ -181,8 +181,8 @@ create a representation in fasta format of following sequence :
 Exercise
 --------
 
-For the following exercise use the python file :download:`sv40 in fasta <_static/code/sv40.py>` which is a python file with the sequence of sv40 in fasta format
-already embeded, and use python -i sv40.py to work.
+For the following exercise use the python file :download:`sv40 in fasta <_static/code/sv40_file.py>` which is a python file with the sequence of sv40 in fasta format
+already embeded, and use python -i sv40_file.py to work.
 
 how long is the sv40 in bp? 
 Hint : the fasta header is 61bp long.
@@ -212,14 +212,15 @@ pseudocode:
 ::
 
    python
-   >>> import sv40
+   >>> import sv40_file
    >>> import fasta_to_one_line
    >>>
-   >>> sv40seq = fasta_to_one_line(sv40) 
-   >>> print len(sv40_sequence)
+   >>> sv40_seq = fasta_to_one_line(sv40_file.sv40_fasta) 
+   >>> print len(sv40_seq)
    5243
 
 Is that the following enzymes: 
+
 * BamHI (ggatcc), 
 * EcorI (gaattc), 
 * HindIII (aagctt), 
diff --git a/source/_static/code/fasta_to_one_line.py b/source/_static/code/fasta_to_one_line.py
index 6ef59c05b921f85ff9fe6886321b83a0f696008e..86b86b9104a5ab01097e31618c6fcb88aa2e6763 100644
--- a/source/_static/code/fasta_to_one_line.py
+++ b/source/_static/code/fasta_to_one_line.py
@@ -1,7 +1,7 @@
 
-def fasta_2_one_line(seq):
-    header_end_at = find('\n')
-    seq = seq[:header_end_at + 1]
+def fasta_to_one_line(seq):
+    header_end_at = seq.find('\n')
+    seq = seq[header_end_at + 1:]
     seq = seq.replace('\n', '')
     return seq