[client] Fix black formatting

Author: Samuel Hassine

pycti/utils/opencti_stix2.py

@@ -327,7 +327,9 @@ def extract_embedded_relationships(self, stix_object, types=None):
                         title = source_name
 
                     if "external_id" in external_reference:
-                        title = title + " (" + str(external_reference["external_id"]) + ")"
+                        title = (
+                            title + " (" + str(external_reference["external_id"]) + ")"
+                        )
 
                     author = self.resolve_author(title)
                     report = self.opencti.report.create(