Add the example code for the fetch timestamp

tools/example/fetch_timestamp.py

@@ -0,0 +1,23 @@
+import sys
+sys.path.append('./')
+
+from substrateinterface import SubstrateInterface
+import datetime
+
+
+if __name__ == '__main__':
+    URL = 'ws://127.0.0.1:10044'
+    substrate = SubstrateInterface(url=URL)
+
+    now_block_num = substrate.get_block_number(None)
+    block_hash = substrate.get_block_hash(now_block_num)
+    block_info = substrate.get_block(block_hash, include_author=True)
+    for extrinsic in block_info['extrinsics']:
+        if extrinsic.value['call']['call_module'] != 'Timestamp':
+            continue
+        if extrinsic.value['call']['call_function'] != 'set':
+            continue
+        timestamp = extrinsic.value['call']['call_args'][0]['value']
+        # Convert time stamp to human readable format
+        human_readable_time = datetime.datetime.fromtimestamp(timestamp / 1000).strftime('%Y-%m-%d %H:%M:%S')
+        print(human_readable_time)