fix: [stix2 import] Making Python 3.9 happy with my return typings be…

…ing str or None

misp_stix_converter/stix2misp/external_stix2_mapping.py

@@ -3,6 +3,7 @@
 
 from .. import Mapping
 from .stix2_mapping import STIX2toMISPMapping
+from typing import Union
 
 
 class ExternalSTIX2toMISPMapping(STIX2toMISPMapping):
@@ -122,13 +123,13 @@ def object_type_refs_to_skip(cls) -> tuple:
         return cls.__object_type_refs_to_skip
 
     @classmethod
-    def observable_mapping(cls, field: str) -> str | None:
+    def observable_mapping(cls, field: str) -> Union[str, None]:
         return cls.__observable_mapping.get(field)
 
     @classmethod
     def opinion_mapping(cls, field: str) -> int:
         return cls.__opinion_mapping.get(field, 50)
 
     @classmethod
-    def stix_object_loading_mapping(cls, field: str) -> str | None:
+    def stix_object_loading_mapping(cls, field: str) -> Union[str, None]:
         return cls.__stix_object_loading_mapping.get(field)

misp_stix_converter/stix2misp/internal_stix2_mapping.py

@@ -3,6 +3,7 @@
 
 from .. import Mapping
 from .stix2_mapping import STIX2toMISPMapping
+from typing import Union
 
 
 class InternalSTIX2toMISPMapping(STIX2toMISPMapping):
@@ -30,5 +31,5 @@ def object_type_refs_to_skip(cls) -> tuple:
         return cls.__object_type_refs_to_skip
 
     @classmethod
-    def stix_object_loading_mapping(cls, field: str) -> str | None:
+    def stix_object_loading_mapping(cls, field: str) -> Union[str, None]:
         return cls.__stix_object_loading_mapping.get(field)

misp_stix_converter/stix2misp/stix2_mapping.py

@@ -3,6 +3,7 @@
 
 from .. import Mapping
 from abc import ABCMeta
+from typing import Union
 
 
 class STIX2toMISPMapping(metaclass=ABCMeta):
@@ -103,15 +104,15 @@ class STIX2toMISPMapping(metaclass=ABCMeta):
     }
 
     @classmethod
-    def bundle_to_misp_mapping(cls, field: str) -> str | None:
+    def bundle_to_misp_mapping(cls, field: str) -> Union[str, None]:
         return cls.__bundle_to_misp_mapping.get(field)
 
     @classmethod
-    def identity_references(cls, identity_id: str) -> str | None:
+    def identity_references(cls, identity_id: str) -> Union[str, None]:
         return cls.__identity_references.get(identity_id)
 
     @classmethod
-    def marking_extension_mapping(cls, field: str) -> str | None:
+    def marking_extension_mapping(cls, field: str) -> Union[str, None]:
         return cls.__marking_extension_mapping.get(field)
 
     @classmethod
@@ -131,5 +132,5 @@ def stix_object_loading_mapping(cls) -> dict:
         return cls.__stix_object_loading_mapping
 
     @classmethod
-    def stix_to_misp_mapping(cls, field: str) -> str | None:
+    def stix_to_misp_mapping(cls, field: str) -> Union[str, None]:
         return cls.__stix_to_misp_mapping.get(field)