diff --git a/python/obitools3/parsers/fasta.pyx b/python/obitools3/parsers/fasta.pyx
index b01dc4b..29ff7c3 100755
--- a/python/obitools3/parsers/fasta.pyx
+++ b/python/obitools3/parsers/fasta.pyx
@@ -104,6 +104,7 @@ def fastaNucIterator(lineiterator,
     cdef bytes      sequence
     cdef int        skipped, ionly, read
     cdef Nuc_Seq    seq
+    cdef bint       stop
     
     if only is None:
         ionly = -1
@@ -130,7 +131,8 @@ def fastaNucIterator(lineiterator,
     else:
         line = firstline       
     
-    while True:
+    stop=False
+    while not stop:
                 
         if ionly >= 0 and read >= ionly:
             break
@@ -153,7 +155,7 @@ def fastaNucIterator(lineiterator,
                 s.append(line[0:-1])
                 line = next(iterator)
         except StopIteration:
-            pass
+            stop=True
         
         sequence  = b"".join(s)        
         
diff --git a/python/obitools3/version.py b/python/obitools3/version.py
index 6fff663..0d94f79 100755
--- a/python/obitools3/version.py
+++ b/python/obitools3/version.py
@@ -1,5 +1,5 @@
 major = 3
 minor = 0
-serial= '0-beta16'
+serial= '0-beta17'
 
 version ="%d.%02d.%s" % (major,minor,serial)