rhui-manager shows "IndexError: pop from empty list"

Issue

• After delete all repositories on rhui-manager, entering 'r' (manage repositories) to add repository on rhui-manager shows an error like:

　IndexError: pop from empty list

• Trying to list repositories by rhui-manager also shows the following error:

# `rhui-manager` repo list

An unexpected error has occurred during the last operation.

pop from empty list

• And error logs are output in rhui.log:

2017-06-12 08:41:25,113 - Unexpected error caught at the shell level
Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/rhui/tools/cli.py", line 66, in run
    Cli.run(self, args)
  File "/usr/lib/python2.7/site-packages/rhui/common/cli.py", line 272, in run
    command_or_section.execute(remaining_args)
  File "/usr/lib/python2.7/site-packages/rhui/common/cli.py", line 113, in execute
    self.method(**arg_dict)
  File "/usr/lib/python2.7/site-packages/rhui/tools/commands/repo.py", line 67, in list
    redhat_repos = self.pulp.redhat_repo_list()
  File "/usr/lib/python2.7/site-packages/rhui/tools/pulp_api.py", line 256, in redhat_repo_list
    repo = self.repo(repo_id)
  File "/usr/lib/python2.7/site-packages/rhui/tools/pulp_api.py", line 178, in repo
    importer = importer_response.response_body.pop()
IndexError: pop from empty list
2017-06-12 08:41:25,127 - pop from empty list
Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/rhui/tools/cli.py", line 66, in run
    Cli.run(self, args)
  File "/usr/lib/python2.7/site-packages/rhui/common/cli.py", line 272, in run
    command_or_section.execute(remaining_args)
  File "/usr/lib/python2.7/site-packages/rhui/common/cli.py", line 113, in execute
    self.method(**arg_dict)
  File "/usr/lib/python2.7/site-packages/rhui/tools/commands/repo.py", line 67, in list
    redhat_repos = self.pulp.redhat_repo_list()
  File "/usr/lib/python2.7/site-packages/rhui/tools/pulp_api.py", line 256, in redhat_repo_list
    repo = self.repo(repo_id)
  File "/usr/lib/python2.7/site-packages/rhui/tools/pulp_api.py", line 178, in repo
    importer = importer_response.response_body.pop()
IndexError: pop from empty list