Optimize XrayAPI functionality and structure

[jcrush2]

get_client = xui.get_client_stats(inbound_id=1, email=id,)

File "/usr/local/lib/python3.7/dist-packages/pyxui/methods/clients.py", line 67, in get_client_stats
get_inbounds = self.get_inbounds()
File "/usr/local/lib/python3.7/dist-packages/pyxui/methods/inbounds.py", line 28, in get_inbounds
return self.verify_response(response)
File "/usr/local/lib/python3.7/dist-packages/pyxui/methods/base.py", line 53, in verify_response
raise errors.NotFound()
pyxui.errors.NotFound: [NOT_FOUND] Error 404 has been received.