Handle no indicators provided in `sms_attachments.py` (#455)

* Handle no indicators provided in `sms_attachments.py`

* Move guard to a more specific place

* Unrelated black formatting

* Related black changes :)

mvt/ios/modules/mixed/calls.py

@@ -69,9 +69,9 @@ class Calls(IOSExtraction):
                     "isodate": convert_mactime_to_iso(row[0]),
                     "duration": row[1],
                     "location": row[2],
-                    "number": row[3].decode("utf-8")
-                    if row[3] and row[3] is bytes
-                    else row[3],
+                    "number": (
+                        row[3].decode("utf-8") if row[3] and row[3] is bytes else row[3]
+                    ),
                     "provider": row[4],
                 }
             )

mvt/ios/modules/mixed/sms_attachments.py

@@ -56,7 +56,9 @@ class SMSAttachments(IOSExtraction):
     def check_indicators(self) -> None:
         for attachment in self.results:
             # Check for known malicious filenames.
-            if self.indicators.check_file_path(attachment["filename"]):
+            if self.indicators and self.indicators.check_file_path(
+                attachment["filename"]
+            ):
                 self.detected.append(attachment)
 
             if (