Allowing explicit passing of the resource group for VNET (#117)

* If the resource group name for VNET is mentioned then that should be used while creating the VNET. If resource group name is not passed, but the names for VNET and SUBNET are passed, then resource group for the workspace will be used while creating the VNET.

* Correcting the directory name for flake-8 check

* Reverting back the change related to flake8

Co-authored-by: Arnab Biswas <arnab.biswas@carrier.com>

dask_cloudprovider/providers/azure/azureml.py

@@ -115,6 +115,18 @@ class AzureMLCluster(Cluster):
 
         Defaults to ``""``.
 
+    vnet: str (optional)
+        Name of the virtual network.
+
+    subnet: str (optional)
+        Name of the subnet inside the virtual network ``vnet``.
+
+    vnet_resource_group: str (optional)
+        Name of the resource group where the virtual network ``vnet``
+        is located. If not passed, but names for ``vnet`` and ``subnet`` are
+        passed, ``vnet_resource_group`` is assigned with the name of resource
+        group associted with ``workspace``
+
     telemetry_opt_out: bool (optional)
         A boolean parameter. Defaults to logging a version of AzureMLCluster
         with Microsoft. Set this flag to False if you do not want to share this
@@ -147,6 +159,7 @@ def __init__(
         admin_ssh_key=None,
         datastores=None,
         code_store=None,
+        vnet_resource_group=None,
         vnet=None,
         subnet=None,
         show_output=False,
@@ -179,6 +192,7 @@ def __init__(
         ## CREATE COMPUTE TARGET
         self.admin_username = admin_username
         self.admin_ssh_key = admin_ssh_key
+        self.vnet_resource_group = vnet_resource_group
         self.vnet = vnet
         self.subnet = subnet
         self.compute_target_set = True
@@ -465,9 +479,12 @@ def __create_compute_target(self):
         ssh_key_pub, self.admin_ssh_key = self.__get_ssh_keys()
 
         if self.vnet and self.subnet:
-            vnet_rg = self.workspace.resource_group
             vnet_name = self.vnet
             subnet_name = self.subnet
+            if self.vnet_resource_group:
+                vnet_rg = self.vnet_resource_group
+            else:
+                vnet_rg = self.workspace.resource_group
 
         try:
             if ct_name not in self.workspace.compute_targets:
@@ -975,3 +992,4 @@ def close(self):
         return to its minimum number of nodes after its idle time before scaledown.
         """
         return self.sync(self._close)
+