viomivacuum doesn´t work with -o json_pretty

[fs79]

/miiocli -o json_pretty viomivacuum --ip x.x.x.x --token x1234567890x status
doesn´t work.
/miiocli viomivacuum --ip x.x.x.x --token x1234567890x status

• OS: Raspbian GNU/Linux 10 \n \l
• python-miio: miiocli, version 0.5.3

Device information:
It doesn´t work for the devicetype "viomivacuum".

Steps to reproduce the behavior:

1. execute the status command with flag "-o json_pretty"

Expected behavior
Should work, the same as for type "vacuum"

Console output
root@loxb01:~# /usr/local/bin/miiocli -o json_pretty viomivacuum --ip x.x.x.x --token x1234567890x status
Traceback (most recent call last):
File "/usr/local/bin/miiocli", line 8, in
sys.exit(create_cli())
File "/usr/local/lib/python3.7/dist-packages/miio/cli.py", line 45, in create_cli
return cli(auto_envvar_prefix="MIIO")
File "/usr/local/lib/python3.7/dist-packages/miio/click_common.py", line 59, in call
return self.main(*args, **kwargs)
File "/usr/local/lib/python3.7/dist-packages/click/core.py", line 782, in main
rv = self.invoke(ctx)
File "/usr/local/lib/python3.7/dist-packages/click/core.py", line 1259, in invoke
return _process_result(sub_ctx.command.invoke(sub_ctx))
File "/usr/local/lib/python3.7/dist-packages/click/core.py", line 1259, in invoke
return _process_result(sub_ctx.command.invoke(sub_ctx))
File "/usr/local/lib/python3.7/dist-packages/click/core.py", line 1066, in invoke
return ctx.invoke(self.callback, **ctx.params)
File "/usr/local/lib/python3.7/dist-packages/click/core.py", line 610, in invoke
return callback(*args, **kwargs)
File "/usr/local/lib/python3.7/dist-packages/miio/click_common.py", line 309, in wrap
click.echo(json.dumps(result, indent=indent))
File "/usr/lib/python3.7/json/init.py", line 238, in dumps
**kw).encode(obj)
File "/usr/lib/python3.7/json/encoder.py", line 201, in encode
chunks = list(chunks)
File "/usr/lib/python3.7/json/encoder.py", line 438, in _iterencode
o = _default(o)
File "/usr/lib/python3.7/json/encoder.py", line 179, in default
raise TypeError(f'Object of type {o.class.name}
TypeError: Object of type ViomiVacuumStatus is not JSON serializable

[rytilahti]

This is happening because ViomiVacuumStatus does not have __json__ method.

[fs79]

@rytilahti
Ok. Who should implement?

[rytilahti]

@fs79 feel free to create a PR :-)