strange condition: Server Group already exists when trying to create it, but then Server Group not found when trying to delete it

code:
`
mx.IsAuthenticated
Out[170]: True

site = mx.get_site('10x')

site.create_server_group(serverGroup, update=False)
Traceback (most recent call last):

File "", line 1, in
site.create_server_group(serverGroup, update=False)

File "/anaconda3/lib/python3.7/site-packages/imperva_sdk-0.2.0-py3.7.egg/imperva_sdk/Site.py", line 113, in create_server_group
return self._connection.create_server_group(Name=Name, Site=self.Name, OperationMode=OperationMode, ProtectedIps=ProtectedIps, ServerIps=ServerIps, update=update)

File "/anaconda3/lib/python3.7/site-packages/imperva_sdk-0.2.0-py3.7.egg/imperva_sdk/MxConnection.py", line 330, in create_server_group
return ServerGroup._create_server_group(connection=self, Name=Name, Site=Site, OperationMode=OperationMode, ProtectedIps=ProtectedIps, ServerIps=ServerIps, update=update)

File "/anaconda3/lib/python3.7/site-packages/imperva_sdk-0.2.0-py3.7.egg/imperva_sdk/ServerGroup.py", line 146, in _create_server_group
raise MxException("Server Group already exists")

MxException: Server Group already exists

site.delete_server_group(serverGroup)
Traceback (most recent call last):

File "", line 1, in
site.delete_server_group(serverGroup)

File "/anaconda3/lib/python3.7/site-packages/imperva_sdk-0.2.0-py3.7.egg/imperva_sdk/Site.py", line 116, in delete_server_group
return self._connection.delete_server_group(Name=Name, Site=self.Name)

File "/anaconda3/lib/python3.7/site-packages/imperva_sdk-0.2.0-py3.7.egg/imperva_sdk/MxConnection.py", line 341, in delete_server_group
return ServerGroup._delete_server_group(connection=self, Name=Name, Site=Site)

File "/anaconda3/lib/python3.7/site-packages/imperva_sdk-0.2.0-py3.7.egg/imperva_sdk/ServerGroup.py", line 161, in _delete_server_group
connection._mx_api('DELETE', '/conf/serverGroups/%s/%s' % (Site, Name))

File "/anaconda3/lib/python3.7/site-packages/imperva_sdk-0.2.0-py3.7.egg/imperva_sdk/MxConnection.py", line 257, in _mx_api
raise MxException("MX returned errors - %s" % str(error_message))

MxException: MX returned errors - [{'description': 'Server Group not found', 'error-code': 'IMP-10008'}]

`

Commencez par reproduire les appels create et delete présentés dans l’issue, puis examinez les méthodes _create_server_group et _delete_server_group de imperva_sdk/ServerGroup.py, ainsi que les chemins d’appel de Site.py et MxConnection.py. Déterminez pourquoi l’API signale des états d’existence contradictoires et établissez le comportement attendu pour la même Server Group avant de valider un correctif.