add subtechniques to stix2 generator

CODE/DISARM-STIX2/objects/relationship.py

@@ -19,3 +19,27 @@ def make_disarm_subtechnique_relationship(source, target):
     )
 
     return relationship
+
+
+def make_disarm_subtechnique_relationships(techniques, subtechniques):
+    """Creates a map of technique and sub-technique.
+
+    Args:
+        techniques (list): List of STIX2 technique objects.
+        subtechniques (list): List of STIX2 subtechnique objects.
+
+    Returns:
+        A Relationship object.
+
+    """
+    technique_ids = {}
+    for technique in techniques:
+        technique_ids[technique["external_references"][0]["external_id"]] = technique["id"]
+
+    relationships = []
+    for subtechnique in subtechniques:
+        technique_id = technique_ids[subtechnique["external_references"][0]["external_id"].split(".")[0]]
+        relationship = make_disarm_subtechnique_relationship(subtechnique["id"], technique_id)
+        relationships.append(relationship)
+
+    return relationships