added possibility to change source and target names in the get_field_mapping method in ParseMapping

cdplib/db_migration/ParseMapping.py

@@ -79,13 +79,19 @@ class ParseMapping:
 
             self._mapping = result
 
-    def get_field_mapping(self) -> dict:
+    def get_field_mapping(self, source_name_tag: str = None, target_name_tag: str = None) -> dict:
         '''
         '''
-        assert(all([set([self._source_name_tag, self._target_name_tag]) <= set(d)
+        if source_name_tag is None:
+            source_name_tag = self._source_name_tag
+
+        if target_name_tag is None:
+            source_name_tag = self._target_name_tag
+
+        assert(all([set([source_name_tag, target_name_tag]) <= set(d)
                     for d in self._mapping]))
 
-        return {d[self._source_name_tag]: d[self._target_name_tag] for d in self._mapping}
+        return {d[source_name_tag]: d[self._target_name_tag] for d in self._mapping}
 
     def _get_fields_satistisfying_condition(self, key: str, value) -> list:
         '''