Add Python examples

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diff --git a/examples/README.md b/examples/README.md
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+# Examples of Zenoh applications communicating with ROS 2 Nodes
+
+This directory contains some examples of applications using the Zenoh APIs only (not ROS 2), and that can communicate with ROS 2 Nodes using CycloneDDS as RMW, via the `zenoh-bridge-ros2dds`.
+
+> :warning: The code of those examples are made to work with the version 0.10.x of the `zenoh-plugin-ros2dds` or `zenoh-bridge-ros2dds`. Soon both will be adapted for compatibility with the incoming `rmw_zenoh`, implying some code change in those examples.
diff --git a/examples/python/README.md b/examples/python/README.md
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+# Examples of Zenoh Python applications communicating with ROS 2 Nodes
+
+
+## Messages Publication: [talker.py](talker.py)
+
+This code mimics the ROS 2 [Topics "talker" demo](https://github.com/ros2/demos/blob/rolling/demo_nodes_cpp/src/topics/talker.cpp). It's compatible with the ROS 2 [Topics "listener" demo](https://github.com/ros2/demos/blob/rolling/demo_nodes_cpp/src/topics/listener.cpp) running those commands:
+- `ros2 run demo_nodes_cpp listener`
+- `zenho-bridge-ros2dds`
+- `python ./talker.py`
+
+## Messages Subscription: [listener.py](listener.py)
+
+This code mimics the ROS 2 [Topics "listener" demo](https://github.com/ros2/demos/blob/rolling/demo_nodes_cpp/src/topics/listener.cpp). It's compatible with the ROS 2 [Topics "talker" demo](https://github.com/ros2/demos/blob/rolling/demo_nodes_cpp/src/topics/talker.cpp) running those commands:
+- `ros2 run demo_nodes_cpp talker`
+- `zenho-bridge-ros2dds`
+- `python ./listener.py`
+
+## Services Client: [add_two_ints_client.py](add_two_ints_client.py)
+
+This code mimics the ROS 2 [Services "add_two_ints_client" demo](https://github.com/ros2/demos/blob/rolling/demo_nodes_cpp/src/services/add_two_ints_client.cpp). It's compatible with the ROS 2 [Services "add_two_ints_server" demo](https://github.com/ros2/demos/blob/rolling/demo_nodes_cpp/src/services/add_two_ints_server.cpp) running those commands:
+- `ros2 run demo_nodes_cpp add_two_ints_server`
+- `zenho-bridge-ros2dds`
+- `python ./add_two_ints_client.py`
+
+## Actions Client: [fibonnacci_action_client.py](fibonnacci_action_client.py)
+
+This code mimics the ROS 2 [Actions "fibonnacci_action_client" demo](https://github.com/ros2/demos/blob/rolling/action_tutorials/action_tutorials_cpp/src/fibonacci_action_client.cpp). It's compatible with the ROS 2 [Actions "fibonnacci_action_server" demo](https://github.com/ros2/demos/blob/rolling/action_tutorials/action_tutorials_cpp/src/fibonacci_action_server.cpp) running those commands:
+- `ros2 run action_tutorials_cpp fibonacci_action_server`
+- `zenho-bridge-ros2dds`
+- `python ./fibonnacci_action_client.py`
diff --git a/examples/python/add_two_ints_client.py b/examples/python/add_two_ints_client.py
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+#
+# Copyright (c) 2024 ZettaScale Technology
+#
+# This program and the accompanying materials are made available under the
+# terms of the Eclipse Public License 2.0 which is available at
+# http://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
+# which is available at https://www.apache.org/licenses/LICENSE-2.0.
+#
+# SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
+#
+# Contributors:
+#   ZettaScale Zenoh Team, <[email protected]>
+#
+import time
+import argparse
+import zenoh
+
+# pycdr2 is the serializer of data in CDR format (required by ROS2)
+import pycdr2
+from pycdr2 import IdlStruct
+from dataclasses import dataclass
+
+# Equivalent to AddTwoInts.Request class, but serializable by pycdr2
+@dataclass
+class AddTwoInts_Request(IdlStruct, typename="AddTwoInts_Request"):
+    a: pycdr2.types.int64
+    b: pycdr2.types.int64
+
+# Equivalent to AddTwoInts.Response class, but serializable by pycdr2
+@dataclass
+class AddTwoInts_Response(IdlStruct, typename="AddTwoInts_Request"):
+    sum: pycdr2.types.int64
+
+def main():
+    parser = argparse.ArgumentParser(
+        prog='add_two_ints_client',
+        description='Zenoh/ROS2 add_two_ints_client example')
+    parser.add_argument('--config', '-c', dest='config',
+        metavar='FILE',
+        type=str,
+        help='A configuration file.')
+    args = parser.parse_args()
+
+    # Create Zenoh Config from file if provoded, or a default one otherwise
+    conf = zenoh.Config.from_file(args.config) if args.config is not None else zenoh.Config()
+    # Open Zenoh Session
+    session = zenoh.open(conf)
+
+    req = AddTwoInts_Request(a=2, b=3)
+    # Send the query with the serialized request
+    replies = session.get('add_two_ints', zenoh.Queue(), value=req.serialize())
+    # Zenoh could get several replies for a request (e.g. from several "Service Servers" using the same name)
+    for reply in replies.receiver:
+        # Deserialize the response
+        rep = AddTwoInts_Response.deserialize(reply.ok.payload)
+        print('Result of add_two_ints: %d' % rep.sum)
+
+    session.close()
+
+
+if __name__ == '__main__':
+    main()
diff --git a/examples/python/fibonnacci_action_client.py b/examples/python/fibonnacci_action_client.py
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+#
+# Copyright (c) 2024 ZettaScale Technology
+#
+# This program and the accompanying materials are made available under the
+# terms of the Eclipse Public License 2.0 which is available at
+# http://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
+# which is available at https://www.apache.org/licenses/LICENSE-2.0.
+#
+# SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
+#
+# Contributors:
+#   ZettaScale Zenoh Team, <[email protected]>
+#
+import time
+import argparse
+import zenoh
+
+# pycdr2 is the serializer of data in CDR format (required by ROS2)
+import pycdr2
+from pycdr2 import IdlStruct
+from dataclasses import dataclass
+
+
+@dataclass
+class Time(IdlStruct, typename="Time"):
+    sec: pycdr2.types.uint32
+    nsec: pycdr2.types.uint32
+
+# Equivalent to Fibonnaci.Goal.Request class, but serializable by pycdr2
+@dataclass
+class Fibonacci_SendGoal_Request(IdlStruct, typename="Fibonacci_SendGoal_Request"):
+    goal_id: pycdr2.types.array[pycdr2.types.uint8, 16]
+    order: pycdr2.types.int32
+
+# Equivalent to Fibonnaci.Goal.Response class, but serializable by pycdr2
+@dataclass
+class Fibonacci_SendGoal_Response(IdlStruct, typename="Fibonacci_SendGoal_Response"):
+    accepted: bool
+    stamp: Time
+
+# Equivalent to Fibonnaci.Goal.Request class, but serializable by pycdr2
+@dataclass
+class Fibonacci_GetResult_Request(IdlStruct, typename="Fibonacci_GetResult_Request"):
+    goal_id: pycdr2.types.array[pycdr2.types.uint8, 16]
+
+# Equivalent to Fibonnaci.Goal.Response class, but serializable by pycdr2
+@dataclass
+class Fibonacci_GetResult_Response(IdlStruct, typename="Fibonacci_GetResult_Response"):
+    status: pycdr2.types.int8
+    sequence: pycdr2.types.sequence[pycdr2.types.int32]
+
+@dataclass
+class Fibonacci_Feedback(IdlStruct, typename="Fibonacci_Feedback"):
+    goal_id: pycdr2.types.array[pycdr2.types.uint8, 16]
+    partial_sequence: pycdr2.types.sequence[pycdr2.types.int32]
+
+
+
+
+def feedback_callback(sample: zenoh.Sample):
+    # Deserialize the message
+    feedback = Fibonacci_Feedback.deserialize(sample.payload)
+    print('Received feedback: {0}'.format(feedback.partial_sequence))
+
+
+def main():
+    parser = argparse.ArgumentParser(
+        prog='fibonacci_action_client',
+        description='Zenoh/ROS2 fibonacci_action_client example')
+    parser.add_argument('--config', '-c', dest='config',
+        metavar='FILE',
+        type=str,
+        help='A configuration file.')
+    args = parser.parse_args()
+
+    # Create Zenoh Config from file if provoded, or a default one otherwise
+    conf = zenoh.Config.from_file(args.config) if args.config is not None else zenoh.Config()
+    # Open Zenoh Session
+    session = zenoh.open(conf)
+
+    # Declare a subscriber for feedbacks
+    pub = session.declare_subscriber('fibonacci/_action/feedback', feedback_callback)
+
+    goal_id = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16]
+    req = Fibonacci_SendGoal_Request(goal_id, order=10)
+    # Send the query with the serialized request
+    replies = session.get('fibonacci/_action/send_goal', zenoh.Queue(), value=req.serialize())
+    # Zenoh could get several replies for a request (e.g. from several "Service Servers" using the same name)
+    for reply in replies.receiver:
+        # Deserialize the response
+        rep = Fibonacci_SendGoal_Response.deserialize(reply.ok.payload)
+        if not rep.accepted:
+            print('Goal rejected :(')
+            return
+
+    print('Goal accepted :)')
+
+    req = Fibonacci_GetResult_Request(goal_id)
+    # Send the query with the serialized request
+    replies = session.get('fibonacci/_action/get_result', zenoh.Queue(), value=req.serialize())
+    # Zenoh could get several replies for a request (e.g. from several "Service Servers" using the same name)
+    for reply in replies.receiver:
+        # Deserialize the response
+        rep = Fibonacci_GetResult_Response.deserialize(reply.ok.payload)
+        print('Result: {0}'.format(rep.sequence))
+
+
+    session.close()
+
+
+if __name__ == '__main__':
+    main()
diff --git a/examples/python/listener.py b/examples/python/listener.py
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+#
+# Copyright (c) 2024 ZettaScale Technology
+#
+# This program and the accompanying materials are made available under the
+# terms of the Eclipse Public License 2.0 which is available at
+# http://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
+# which is available at https://www.apache.org/licenses/LICENSE-2.0.
+#
+# SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
+#
+# Contributors:
+#   ZettaScale Zenoh Team, <[email protected]>
+#
+import time
+import argparse
+import zenoh
+
+# pycdr2 is the serializer of data in CDR format (required by ROS2)
+from pycdr2 import IdlStruct
+from dataclasses import dataclass
+
+# Equivalent to std_msgs.msg.String class, but serializable by pycdr2
+@dataclass
+class String(IdlStruct, typename="String"):
+    data: str
+
+def chatter_callback(sample: zenoh.Sample):
+    # Deserialize the message
+    msg = String.deserialize(sample.payload)
+    print('I heard: [%s]' % msg.data)
+
+def main():
+    parser = argparse.ArgumentParser(
+        prog='listener',
+        description='Zenoh/ROS2 listener example')
+    parser.add_argument('--config', '-c', dest='config',
+        metavar='FILE',
+        type=str,
+        help='A configuration file.')
+    args = parser.parse_args()
+
+    # Create Zenoh Config from file if provoded, or a default one otherwise
+    conf = zenoh.Config.from_file(args.config) if args.config is not None else zenoh.Config()
+    # Open Zenoh Session
+    session = zenoh.open(conf)
+
+    # Declare a subscriber
+    pub = session.declare_subscriber('chatter', chatter_callback)
+
+    try:
+        while True:
+            time.sleep(1)
+    except (KeyboardInterrupt):
+        pass
+    finally:
+        pub.undeclare()
+        session.close()
+
+
+if __name__ == '__main__':
+    main()
diff --git a/examples/python/talker.py b/examples/python/talker.py
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+#
+# Copyright (c) 2024 ZettaScale Technology
+#
+# This program and the accompanying materials are made available under the
+# terms of the Eclipse Public License 2.0 which is available at
+# http://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
+# which is available at https://www.apache.org/licenses/LICENSE-2.0.
+#
+# SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
+#
+# Contributors:
+#   ZettaScale Zenoh Team, <[email protected]>
+#
+import time
+import argparse
+import zenoh
+
+# pycdr2 is the serializer of data in CDR format (required by ROS2)
+from pycdr2 import IdlStruct
+from dataclasses import dataclass
+
+# Equivalent to std_msgs.msg.String class, but serializable by pycdr2
+@dataclass
+class String(IdlStruct, typename="String"):
+    data: str
+
+def main():
+    parser = argparse.ArgumentParser(
+        prog='talker',
+        description='Zenoh/ROS2 talker example')
+    parser.add_argument('--config', '-c', dest='config',
+        metavar='FILE',
+        type=str,
+        help='A configuration file.')
+    args = parser.parse_args()
+
+    # Create Zenoh Config from file if provoded, or a default one otherwise
+    conf = zenoh.Config.from_file(args.config) if args.config is not None else zenoh.Config()
+    # Open Zenoh Session
+    session = zenoh.open(conf)
+
+    # Declare a publisher (optional but allows Zenoh to perform some optimizations)
+    pub = session.declare_publisher('chatter')
+
+    try:
+        i = 0
+        while True:
+            i += 1
+            msg = String(data='Hello World: {0}'.format(i))
+            print('Publishing: "{0}"'.format(msg.data))
+            # Publish the serialized message
+            pub.put(msg.serialize())
+            time.sleep(1)
+
+    except (KeyboardInterrupt):
+        pass
+    finally:
+        pub.undeclare()
+        session.close()
+
+
+if __name__ == '__main__':
+    main()