diff --git a/iers2py.py b/iers2py.py
index 6f68eb1..b8aea06 100755
--- a/iers2py.py
+++ b/iers2py.py
@@ -104,7 +104,7 @@ def better(off0, off1):
 print("dut1_data_start = %r" % start)
 c = sorted(chr(ord("a") + ch + 10) for ch in set(offsets))
 print("%s = '%s'" % (",".join(c), "".join(c)))
-print("dut1_offsets = ( # %04d%02d%02d" % (start.year, start.month, start.day))
+print("dut1_offsets = str( # %04d%02d%02d" % (start.year, start.month, start.day))
 line = ""
 now = start
 j = 0
diff --git a/iersdata.py b/iersdata.py
index 3624b57..051b7b5 100644
--- a/iersdata.py
+++ b/iersdata.py
@@ -5,7 +5,7 @@
 __all__ = ['dut1_data_start, dut1_offsets']
 dut1_data_start = datetime.datetime(1973, 1, 2, 0, 0)
 d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s = 'defghijklmnopqrs'
-dut1_offsets = ( # 19730102
+dut1_offsets = str( # 19730102
     s*18+r*31+q*29+p*28+o*30+n*36+m*40+l*39+k*33+j*31+i*31+h*18  # 19740119
     +r*19+q*38+p*32+o*31+n*33+m*48+l*45+k*37+j*33+i*34+h*15+r*22 # 19750225
     +q*34+p*33+o*34+n*37+m*49+l*45+k*36+j*32+i*36+h*7+r*28+q*33  # 19760402