Describe the bug
Hi, I'm using RRDtool 1.7.2 on Ubuntu 20.04. I,m trying to create cumulative graph with rrdtool graph args but failing to do it.

Script
rrdtool graphv /root/sources/noc-rrd/rrd_graphs/crk1.png --title crk1 --width 1200 --height 300 --start now-8h --end now --lower-limit=0 --interlaced --slope-mode --imgformat PNG DEF:ds0=/root/sources/noc-rrd/rrd_databases/vpses/crk1-A.rrd:ds:AVERAGE CDEF:cdef0=ds0 AREA:cdef0#4c0303:STACK:A GPRINT:cdef0:LAST:'Current:%6.0lf' GPRINT:cdef0:AVERAGE:'Average:%6.0lf' GPRINT:cdef0:MAX:'Maximum:%6.0lf' DEF:ds1=/root/sources/noc-rrd/rrd_databases/vpses/crk1-B.rrd:ds:AVERAGE CDEF:cdef1=ds1 AREA:cdef1#423204:STACK:B GPRINT:cdef1:LAST:'Current:%6.0lf' GPRINT:cdef1:AVERAGE:'Average:%6.0lf' GPRINT:cdef1:MAX:'Maximum:%6.0lf\n' DEF:ds2=/root/sources/noc-rrd/rrd_databases/vpses/crk1-C.rrd:ds:AVERAGE CDEF:cdef2=ds2 AREA:cdef2#2c5206:STACK:C GPRINT:cdef2:LAST:Current:%6.0lf GPRINT:cdef2:AVERAGE:Average:%6.0lf GPRINT:cdef2:MAX:Maximum:%6.0lf DEF:ds3=/root/sources/noc-rrd/rrd_databases/vpses/crk1-D.rrd:ds:AVERAGE CDEF:cdef3=ds3 AREA:cdef3#024c14:STACK:D GPRINT:cdef3:LAST:Current:%6.0lf GPRINT:cdef3:AVERAGE:Average:%6.0lf GPRINT:cdef3:MAX:Maximum:%6.0lf\n DEF:ds4=/root/sources/noc-rrd/rrd_databases/vpses/crk1-E.rrd:ds:AVERAGE CDEF:cdef4=ds4 AREA:cdef4#0d4a4a:STACK:E GPRINT:cdef4:LAST:Current:%6.0lf GPRINT:cdef4:AVERAGE:Average:%6.0lf GPRINT:cdef4:MAX:Maximum:%6.0lf DEF:ds5=/root/sources/noc-rrd/rrd_databases/vpses/crk1-F.rrd:ds:AVERAGE CDEF:cdef5=ds5 AREA:cdef5#05164a:STACK:F GPRINT:cdef5:LAST:Current:%6.0lf GPRINT:cdef5:AVERAGE:Average:%6.0lf GPRINT:cdef5:MAX:Maximum:%6.0lf\n DEF:ds6=/root/sources/noc-rrd/rrd_databases/vpses/crk1-G.rrd:ds:AVERAGE CDEF:cdef6=ds6 AREA:cdef6#26014b:STACK:G GPRINT:cdef6:LAST:Current:%6.0lf GPRINT:cdef6:AVERAGE:Average:%6.0lf GPRINT:cdef6:MAX:Maximum:%6.0lf DEF:ds7=/root/sources/noc-rrd/rrd_databases/vpses/crk1-H.rrd:ds:AVERAGE CDEF:cdef7=ds7 AREA:cdef7#460837:STACK:H GPRINT:cdef7:LAST:Current:%6.0lf GPRINT:cdef7:AVERAGE:Average:%6.0lf GPRINT:cdef7:MAX:Maximum:%6.0lf\n

To Reproduce
Steps to reproduce the behavior:

1. Create few rrds and fill it with data
2. run with cli
3. See error (ERROR: Unused Arguments "%6.0lf" in command : GPRINT:cdef0:LAST:Current:%6.0lf)

Expected behavior
Sould create graph, note that script work on debian 10, can create a graph with one rrd, more then one result with error

Desktop (please complete the following information):

• OS: Ubuntu 20.04 (Linux xxx 5.4.60-1-pve Port RRDtool from libart to Cairo #1 SMP PVE 5.4.60-2 x86_64 x86_64 x86_64 GNU/Linux)
• rrdtool: RRDtool 1.7.2 (1.7.2-3build2)

Additional context
Add any other context about the problem here.