commit 6bd35122cc096acff6cd4bd93cc06f2e5f8fd354
Author: Federico Ressi <fressi@redhat.com>
Date:   Wed Oct 14 13:27:41 2020 +0200

    Add typing annotation to selection tools
    
    Change-Id: I107fef91fc8d087d5470c2d8e141c7fe76930fb1

diff --git a/tobiko/common/_select.py b/tobiko/common/_select.py
index 5697807..dce2088 100644
--- a/tobiko/common/_select.py
+++ b/tobiko/common/_select.py
@@ -13,10 +13,15 @@
 #    under the License.
 from __future__ import absolute_import
 
+import typing  # noqa
+
 from tobiko import _exception
 
 
-class Selection(list):
+T = typing.TypeVar('T')
+
+
+class Selection(list, typing.Generic[T]):
 
     def with_attributes(self, **attributes):
         return self.create(
@@ -33,18 +38,18 @@ class Selection(list):
         return self.create(filter_by_items(self, exclude=True, **items))
 
     @classmethod
-    def create(cls, objects):
+    def create(cls, objects: typing.Iterable[T]):
         return cls(objects)
 
     @property
-    def first(self):
+    def first(self) -> T:
         if self:
             return self[0]
         else:
             raise ObjectNotFound()
 
     @property
-    def unique(self):
+    def unique(self) -> T:
         if len(self) > 1:
             raise MultipleObjectsFound(list(self))
         else:
@@ -54,7 +59,7 @@ class Selection(list):
         return '{!s}({!r})'.format(type(self).__name__, list(self))
 
 
-def select(objects):
+def select(objects: typing.Iterable[T]) -> Selection[T]:
     return Selection.create(objects)
 
 
diff --git a/tobiko/openstack/tests/_nova.py b/tobiko/openstack/tests/_nova.py
index 1485bae..78b91b7 100644
--- a/tobiko/openstack/tests/_nova.py
+++ b/tobiko/openstack/tests/_nova.py
@@ -58,14 +58,14 @@ def test_server_creation_and_shutoff(stack=TestServerCreationStack):
 
 def test_servers_creation(stack=TestServerCreationStack,
                           number_of_servers=2) -> \
-        typing.List[_nova.ServerStackFixture]:
+        tobiko.Selection[_nova.ServerStackFixture]:
 
     initial_servers_ids = {server.id for server in nova.list_servers()}
     pid = os.getpid()
     fixture_obj = tobiko.get_fixture_class(stack)
 
     # Get list of server stack instances
-    fixtures = tobiko.Selection(
+    fixtures: tobiko.Selection[_nova.ServerStackFixture] = tobiko.select(
         tobiko.get_fixture(fixture_obj, fixture_id=f'{pid}-{i}')
         for i in range(number_of_servers or 1))
 
diff --git a/tobiko/openstack/topology/_address.py b/tobiko/openstack/topology/_address.py
index 3adeca0..7a81188 100644
--- a/tobiko/openstack/topology/_address.py
+++ b/tobiko/openstack/topology/_address.py
@@ -32,7 +32,7 @@ def list_addresses(obj,
                    ip_version: typing.Optional[int] = None,
                    port: typing.Union[int, str, None] = None,
                    ssh_config: bool = False) -> \
-        typing.List[netaddr.IPAddress]:
+        tobiko.Selection[netaddr.IPAddress]:
     if isinstance(obj, tobiko.Selection):
         addresses = obj
     elif isinstance(obj, netaddr.IPAddress):
@@ -58,7 +58,7 @@ def list_host_addresses(host: str,
                         ip_version: typing.Optional[int] = None,
                         port: typing.Union[int, str, None] = None,
                         ssh_config: bool = False) -> \
-        typing.List[netaddr.IPAddress]:
+        tobiko.Selection[netaddr.IPAddress]:
 
     if not port:
         if ssh_config:
@@ -66,7 +66,7 @@ def list_host_addresses(host: str,
         else:
             port = 0
 
-    addresses = []
+    addresses: tobiko.Selection[netaddr.IPAddress] = tobiko.Selection()
     hosts = [host]
     resolved = set()
     while hosts:
diff --git a/tobiko/openstack/topology/_topology.py b/tobiko/openstack/topology/_topology.py
index 639f0be..2a4c955 100644
--- a/tobiko/openstack/topology/_topology.py
+++ b/tobiko/openstack/topology/_topology.py
@@ -323,18 +323,19 @@ class OpenStackTopology(tobiko.SharedFixture):
             self._groups[group] = nodes = self.create_group()
             return nodes
 
-    def create_group(self) -> tobiko.Selection:
+    @staticmethod
+    def create_group() -> tobiko.Selection[OpenStackTopologyNode]:
         return tobiko.Selection()
 
-    def get_group(self, group) -> tobiko.Selection:
+    def get_group(self, group) -> tobiko.Selection[OpenStackTopologyNode]:
         try:
             return self._groups[group]
         except KeyError as ex:
             raise _exception.NoSuchOpenStackTopologyNodeGroup(
                 group=group) from ex
 
-    def get_groups(self, groups) -> tobiko.Selection:
-        nodes = tobiko.Selection()
+    def get_groups(self, groups) -> tobiko.Selection[OpenStackTopologyNode]:
+        nodes: tobiko.Selection[OpenStackTopologyNode] = tobiko.Selection()
         for group in groups:
             nodes.extend(self.get_group(group))
         return nodes
diff --git a/tobiko/shell/ip.py b/tobiko/shell/ip.py
index e54bb3e..2dd7df5 100644
--- a/tobiko/shell/ip.py
+++ b/tobiko/shell/ip.py
@@ -41,7 +41,7 @@ INETS = {
 
 def list_ip_addresses(ip_version: typing.Optional[int] = None,
                       scope: str = None, **execute_params) -> \
-        typing.List[netaddr.IPAddress]:
+        tobiko.Selection[netaddr.IPAddress]:
     inets = INETS.get(ip_version)
     if inets is None:
         error = "invalid IP version: {!r}".format(ip_version)
@@ -49,7 +49,7 @@ def list_ip_addresses(ip_version: typing.Optional[int] = None,
 
     output = execute_ip(['-o', 'address', 'list'], **execute_params)
 
-    ips = tobiko.Selection()
+    ips: tobiko.Selection[netaddr.IPAddress] = tobiko.Selection()
     if output:
         for line in output.splitlines():
             fields = line.strip().split()