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'}]

`

Inizia riproducendo le chiamate create e delete mostrate nell’issue, quindi esamina i metodi _create_server_group e _delete_server_group in imperva_sdk/ServerGroup.py, insieme ai percorsi delle chiamate di Site.py e MxConnection.py. Determina perché l’API segnala stati di esistenza in conflitto e stabilisci il comportamento previsto per la stessa Server Group prima di validare una correzione.