Add get_obj function to bundle.py to make accessing bundles easier

stix2/test/v21/test_bundle.py

@@ -183,6 +183,8 @@ def test_parse_bundle(version):
     assert bundle.objects[0].type == 'indicator'
     assert bundle.objects[1].type == 'malware'
     assert bundle.objects[2].type == 'relationship'
+    assert bundle.get_obj('malware--00000000-0000-4000-8000-000000000003').type == 'malware'
+    assert bundle.get_obj('blah blah') is None
 
 
 def test_parse_unknown_type():

stix2/v21/bundle.py

@@ -33,3 +33,6 @@ class Bundle(_STIXBase):
         self._properties['objects'].contained.allow_custom = kwargs.get('allow_custom', False)
 
         super(Bundle, self).__init__(**kwargs)
+
+    def get_obj(self, obj_uuid):
+        return next((elem for elem in self.objects if elem['id'] == obj_uuid), None)