diff --git a/python/obitools3/format/fastq.pyx b/python/obitools3/format/fastq.pyx
index b149187..9aea233 100644
--- a/python/obitools3/format/fastq.pyx
+++ b/python/obitools3/format/fastq.pyx
@@ -19,11 +19,12 @@ cdef class FastqFormat:
 		
 		cdef bytes quality	
 		
+		quality = None
 		if hasattr(data, "quality_bytes"):
 			quality = data.quality_bytes
 		elif hasattr(data, "quality"):
 			quality = tobytes(data.quality)
-		else:
+		if quality is None:
 			raise AttributeError("No quality when exporting to fastq")  # TODO discuss
 		
 		return self.headerFormatter(data) + b"\n" + data[NUC_SEQUENCE_COLUMN] + b"\n+\n" + quality