Add OpenSERP SDK usage examples

examples/content/python-extract-markdown/README.md

@@ -0,0 +1,10 @@
+# Extract a page to Markdown (Python)
+
+Extracts one URL with `/extract` and writes the cleaned page content to `extracted.md`.
+
+```bash
+pip install -r requirements.txt
+python main.py
+```
+
+Edit the `url` in [main.py](main.py) to extract a different page.