corrected save_contigs function

debruijn/debruijn.py

 """
 Small assembly module based on de bruijn graphs
 """
+import os
 import networkx as nx
 from networkx import algorithms
 
 def select_best_path():
     pass
 
+def fill(text, width=80):
+    """Split text with a line return to respect fasta format"""
+    return os.linesep.join(text[i:i+width] for i in range(0, len(text), width))
 
 def save_contigs(tuples, outname):
     """
         tuples, tuple: Obtained from get_contigs()
         outname, str: name of the file to be written
     """
+    i = 0
     with open(outname, "w") as outfile:
         for duo in tuples:
-            outfile.write("{} {}".format(duo[0], duo[1]))
+            i += 1
+            outfile.write(">contig_{} len={}\n".format(i, duo[1]))
+            outfile.write("{}\n".format(fill(duo[0])))
 
     return