guest_create_network_interface for SLES12 guest failed with syntax error

request and response error info:

SDKBaseException: SDK request guest_create_network_interface failed with parameters: ('SYDYFVT1', 'sles12', [{'gateway_addr': '9.60.29.1', 'ip_addr': '9.60.29.41'}]) {} . Error messages: Unexpected internal error in ZVM SDK, error: (127.0.0.1:45778) SDK server got unexpected exception: ValueError("invalid literal for int() with base 10: ''",)

zvmsdk.log:

[2018-05-14 01:29:48] [DEBUG] Creating network configuration files for guest SYDYFVT1 in the folder /tmp/SYDYFVT1zgM_nX
[2018-05-14 01:29:48] [ERROR] (127.0.0.1:45778) Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/zVMCloudConnector-1.1.0-py2.7.egg/zvmsdk/sdkserver.py", line 146, in serve_API
    return_data = api_func(*api_args, **api_kwargs)
  File "/usr/lib/python2.7/site-packages/zVMCloudConnector-1.1.0-py2.7.egg/zvmsdk/api.py", line 1220, in guest_create_network_interface
    active=active)
  File "/usr/lib/python2.7/site-packages/zVMCloudConnector-1.1.0-py2.7.egg/zvmsdk/networkops.py", line 126, in network_configuration
    active=active)
  File "/usr/lib/python2.7/site-packages/zVMCloudConnector-1.1.0-py2.7.egg/zvmsdk/networkops.py", line 156, in _generate_network_doscript
    first, active=active)
  File "/usr/lib/python2.7/site-packages/zVMCloudConnector-1.1.0-py2.7.egg/zvmsdk/dist.py", line 92, in create_network_configuration_files
    base_vdev, active=active)
  File "/usr/lib/python2.7/site-packages/zVMCloudConnector-1.1.0-py2.7.egg/zvmsdk/dist.py", line 149, in _generate_network_configuration
    subchannels)
  File "/usr/lib/python2.7/site-packages/zVMCloudConnector-1.1.0-py2.7.egg/zvmsdk/dist.py", line 467, in _get_cfg_str
    cidr_v4 = self._get_cidr_from_ip_netmask(ip_v4, netmask_v4)
  File "/usr/lib/python2.7/site-packages/zVMCloudConnector-1.1.0-py2.7.egg/zvmsdk/dist.py", line 460, in _get_cidr_from_ip_netmask
    bin_str += bin(int(octet))[2:].zfill(8)
ValueError: invalid literal for int() with base 10: ''

This error would be triggered if guest is sles and netmask is not specified.