AttributeError: 'module' object has no attribute 'get_warnings' in subscription-manager command

Issue

The registration with subscription-manager command failed with the following error:

Traceback (most recent call last):
  File "/usr/lib64/python2.7/site-packages/subscription_manager/managercli.py", line 1389, in _do_command
    type=self.options.consumertype
  File "/usr/lib64/python2.7/site-packages/rhsmlib/services/register.py", line 66, in register
    facts_dict = self.facts.get_facts()
  File "/usr/lib64/python2.7/site-packages/subscription_manager/facts.py", line 78, in get_facts
    facts = collector.get_all()
  File "/usr/lib64/python2.7/site-packages/rhsmlib/facts/all.py", line 35, in get_all
    results.update(fact_collector.get_all())
  File "/usr/lib64/python2.7/site-packages/rhsmlib/facts/host_collector.py", line 56, in get_all
    firmware_info_dict = firmware_collector.get_all()
  File "/usr/lib64/python2.7/site-packages/rhsmlib/facts/firmware_info.py", line 69, in get_all
    firmware_info = self.get_firmware_info()
  File "/usr/lib64/python2.7/site-packages/rhsmlib/facts/firmware_info.py", line 62, in get_firmware_info
    firmware_info_dict = firmware_info_collector.get_all()
  File "/usr/lib64/python2.7/site-packages/rhsmlib/facts/dmiinfo.py", line 93, in get_all
    self.log_warnings(dmidecode)
  File "/usr/lib64/python2.7/site-packages/rhsmlib/facts/dmiinfo.py", line 128, in log_warnings
    dmiwarnings = dmidecode.get_warnings()
AttributeError: 'module' object has no attribute 'get_warnings'