[doc] Add better syntax highlighting and example (#96)

* [doc] Add better syntax highlighting and example
* Black formatting

Author: rhaist

docs/client_usage/getting_started.rst

@@ -8,14 +8,37 @@ Please install the latest pycti version available from PyPI::
 
     $ pip3 install pycti
 
-Initialization
-**************
+Using the helper functions
+**************************
 
-The main class contains all what you need to interact with the platform,
-you just have to initialize it::
+The main class :class:`OpenCTIApiClient` contains all what you need to interact
+with the platform, you just have to initialize it. The following example shows
+how you create an indicator in OpenCTI using the python library with TLP marking
+and OpenCTI compatible date format.
 
-    # coding: utf-8
+.. code-block:: python
+
+    from dateutil.parser import parse
     from pycti import OpenCTIApiClient
+    from stix2 import TLP_GREEN
+
+    # OpenCTI API client initialization
+    opencti_api_client = OpenCTIApiClient("https://myopencti.server", "mysupersecrettoken")
+
+    # Define an OpenCTI compatible date
+    date = parse("2019-12-01").strftime("%Y-%m-%dT%H:%M:%SZ")
+
+    # Get the OpenCTI marking for stix2 TLP_GREEN
+    TLP_GREEN_CTI = opencti_api_client.marking_definition.read(id=TLP_GREEN["id"])
 
-    # OpenCTI initialization
-    opencti_api_client = OpenCTIApiClient(api_url, api_token, log_level, ssl_verify)
+    # Use the client to create an indicator in OpenCTI
+    indicator = opencti_api_client.indicator.create(
+        name="C2 server of the new campaign",
+        description="This is the C2 server of the campaign",
+        pattern_type="stix",
+        indicator_pattern="[domain-name:value = 'www.5z8.info']",
+        main_observable_type="IPv4-Addr",
+        valid_from=date,
+        update=True,
+        markingDefinitions=[TLP_GREEN_CTI["id"]],
+    )

docs/conf.py

@@ -29,6 +29,8 @@
 
 autoapi_modules = {"pycti": {"prune": True}}
 
+pygments_style = "sphinx"
+
 # -- General configuration ---------------------------------------------------
 
 # Add any Sphinx extension module names here, as strings. They can be