Description of problem:
Autopartitioning. Specified thin provisioning partition type. In the main spoke the status was waiting while saving storage selection, then crashed.

Version-Release number of selected component:
anaconda-20.18-1

The following was filed automatically by anaconda:
anaconda 20.18-1 exception report
Traceback (most recent call first):
  File "/usr/lib/python2.7/site-packages/blivet/devices.py", line 2615, in vgSpaceUsed
    + self.logSize + self.metaDataSize)
  File "/usr/lib/python2.7/site-packages/blivet/devices.py", line 2847, in vgSpaceUsed
    space = super(LVMThinPoolDevice, self).vgSpaceUsed
  File "/usr/lib/python2.7/site-packages/blivet/devices.py", line 2409, in <genexpr>
    used = sum(lv.vgSpaceUsed for lv in self.lvs) + self.snapshotSpace
  File "/usr/lib/python2.7/site-packages/blivet/devices.py", line 2409, in freeSpace
    used = sum(lv.vgSpaceUsed for lv in self.lvs) + self.snapshotSpace
  File "/usr/lib/python2.7/site-packages/blivet/devices.py", line 2296, in _addLogVol
    lv.size > self.freeSpace:
  File "/usr/lib/python2.7/site-packages/blivet/devices.py", line 2564, in __init__
    self.parents[0]._addLogVol(self)
  File "/usr/lib/python2.7/site-packages/blivet/__init__.py", line 1144, in newLV
    return device_class(name, *args, **kwargs)
  File "/usr/lib/python2.7/site-packages/blivet/partitioning.py", line 282, in _scheduleVolumes
    dev = new_volume(**kwargs)
  File "/usr/lib/python2.7/site-packages/blivet/partitioning.py", line 321, in doAutoPartition
    _scheduleVolumes(storage, devs)
  File "/usr/lib64/python2.7/site-packages/pyanaconda/kickstart.py", line 244, in execute
    doAutoPartition(storage, ksdata)
  File "/usr/lib64/python2.7/site-packages/pyanaconda/kickstart.py", line 1678, in doKickstartStorage
    ksdata.autopart.execute(storage, ksdata, instClass)
  File "/usr/lib64/python2.7/site-packages/pyanaconda/ui/gui/spokes/storage.py", line 420, in _doExecute
    doKickstartStorage(self.storage, self.data, self.instclass)
  File "/usr/lib64/python2.7/threading.py", line 764, in run
    self.__target(*self.__args, **self.__kwargs)
  File "/usr/lib64/python2.7/site-packages/pyanaconda/threads.py", line 168, in run
    threading.Thread.run(self, *args, **kwargs)
TypeError: unsupported operand type(s) for +: 'long' and 'NoneType'

Additional info:
cmdline:        /usr/bin/python  /sbin/anaconda
cmdline_file:   BOOT_IMAGE=/images/pxeboot/vmlinuz inst.stage2=hd:LABEL=Fedora\x2020-Alpha\x20x86_64 quiet
executable:     /sbin/anaconda
hashmarkername: anaconda
kernel:         3.11.0-300.fc20.x86_64
product:        Fedora
release:        Cannot get release name.
type:           anaconda
version:        20-Alpha