'NoneType' object has no attribute 'status'

-------------------- >> begin captured logging << --------------------
ovirtlago.testlib: ERROR:     * Unhandled exception in <function <lambda> at 0x7f5e9feb3ed8>
Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/ovirtlago/testlib.py", line 234, in assert_equals_within
    res = func()
  File "/home/jenkins/workspace/ovirt-master_change-queue-tester/ovirt-system-tests/basic-suite-master/test-scenarios/004_basic_sanity.py", line 1153, in <lambda>
    lambda: api.disks.get(disk_name).status.state == 'ok',
AttributeError: 'NoneType' object has no attribute 'status'
--------------------- >> end captured logging << -------------