diff --git a/src/datadoc/backend/dapla_dataset_path_info.py b/src/datadoc/backend/dapla_dataset_path_info.py
index 8604edd1..319b4125 100644
--- a/src/datadoc/backend/dapla_dataset_path_info.py
+++ b/src/datadoc/backend/dapla_dataset_path_info.py
@@ -15,18 +15,18 @@
 
 
 class SupportedDateFormats(Enum):
+    """The Date formats supported by the naming convention."""
     ISO_YEAR = auto() # String format YYYY
     ISO_YEAR_MONTH = auto() # String format YYYY-MM
     ISO_YEAR_MONTH_DAY = auto() # String format YYYY-MM-DD
-    SSB_YEAR_SEME TER= auto()
- # String format YYYY-Hn
-    SSB_YEAR_TRIMESTER = auto() # String format YYYY-Tn
+    SSB_YEAR_SEMESTER = auto()    SSB_YEAR_TRIMESTER = auto() # String format YYYY-Tn
     SSB_YEAR_QUARTER = auto() # String format YYYY-Qn
     SSB_YEAR_BIMESTER = auto() # String format YYYY-Bn
     SSB_YEAR_WEEK = auto() # String format YYYY-Wnn
 
+
 class RegexEqual(str):
-    """Helper class for structual pattern matching using regex""""
+    """Helper class for structual pattern matching using regex."""
     def __eq__(self, pattern:str)->bool:
         return bool(re.search(pattern, self))
 
@@ -48,10 +48,10 @@ def __init__(self, dataset_path: str) -> None:
             self.second_period_string = _period_strings[1]
 
 
-    def _categorize_period_string(period: str) -> SupportedDateFormats:
+    def _categorize_period_string(self,period: str) -> SupportedDateFormats:
         """A naive string validator."""
         match RegexEqual(period):
-            case "\d+":
+            case r"\d+":
                 return SupportedDateFormats.ISO_YEAR