diff --git a/adafruit_miniqr.py b/adafruit_miniqr.py
index 0863636..02bd98e 100644
--- a/adafruit_miniqr.py
+++ b/adafruit_miniqr.py
@@ -93,7 +93,7 @@ def __init__(self, *, qr_type=None, error_correct=L):
     def add_data(self, data):
         """Add more data to the QR code, must be bytestring stype"""
         self.data_list.append(data)
-        datalen = sum([len(x) for x in self.data_list])
+        datalen = sum(len(x) for x in self.data_list)
         if not self.type:
             for qr_type in range(1, 6):
                 rs_blocks = _get_rs_blocks(qr_type, self.ECC)