Unexpected keyword argument 'v4' when trying to list subnets with SLCLI

[acamacho82]

Subnets are not listed when calling to slcli subnet list, this happens in the latest version 5.6.0

Actual Behavior

$ slcli subnet list
An unexpected error has occured:
Traceback (most recent call last):
  File "/home/acamacho/.local/lib/python2.7/site-packages/SoftLayer/CLI/core.py", line 182, in main
    cli.main(**kwargs)
  File "/usr/local/lib/python2.7/dist-packages/click/core.py", line 717, in main
    rv = self.invoke(ctx)
  File "/usr/local/lib/python2.7/dist-packages/click/core.py", line 1137, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/usr/local/lib/python2.7/dist-packages/click/core.py", line 1137, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/usr/local/lib/python2.7/dist-packages/click/core.py", line 956, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/usr/local/lib/python2.7/dist-packages/click/core.py", line 555, in invoke
    return callback(*args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/click/decorators.py", line 64, in new_func
    return ctx.invoke(f, obj, *args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/click/core.py", line 555, in invoke
    return callback(*args, **kwargs)
TypeError: cli() got an unexpected keyword argument 'v4'

Feel free to report this error as it is likely a bug:
    https://github.com/softlayer/softlayer-python/issues
The following snippet should be able to reproduce the error

Environment Information

Operating System: Linux
softlayer-python version (slcli --version): 5.6.0

[acamacho82]

It seems the issue is here, checking..

softlayer-python/SoftLayer/CLI/subnet/list.py

Line 29 in 8a755be

@click.option('--v4', '--ipv4', is_flag=True, help="Display only IPv4 subnets")

[acamacho82]

dup of #1060