Added logic to skip conversion from str to datetime

plio/io/isis_serial_number.py

@@ -2,6 +2,7 @@ import warnings
 
 import pvl
 from pvl.collections import PVLModule
+from itertools import chain
 
 import plio
 from plio.data import get_data
@@ -97,10 +98,6 @@ def generate_serial_number(label):
                 serial_entry = search_translation[serial_entry]
             elif '*' in search_translation.keys() and search_translation['*'] != '*':
                 serial_entry = search_translation['*']
-            try:
-                serial_entry = serial_entry.strftime("%Y-%m-%dT%H:%M:%S.%f")[:-3]
-            except:
-                pass
             serial_number.append(serial_entry)
         except:
             pass
@@ -114,13 +111,69 @@ class SerialNumberDecoder(pvl.decoder.PVLDecoder):
     serial number. Inherits from the PVLDecoder in planetarypy's pvl module.
     """
 
-    def cast_unquoted_string(self, value):
+    def decode_simple_value(self, value: str):
+        """Returns a Python object based on *value*, assuming
+        that *value* can be decoded as a PVL Simple Value::
+
+         <Simple-Value> ::= (<Numeric> | <String>)
+
+         Modified from https://pvl.readthedocs.io/en/stable/_modules/pvl/decoder.html#PVLDecoder.decode_simple_value
+         Modification entails stripping datetime from list of functions.
         """
-        Overrides the parent class's method so that any un-quoted string type value found in the
-        parsed pvl will just return the original value. This is needed so that keyword values
-        are not re-formatted from what is originally in the ISIS cube label.
+        for d in (
+            self.decode_quoted_string,
+            self.decode_non_decimal,
+            self.decode_decimal,
+        ):
+            try:
+                return d(value)
+            except ValueError:
+                pass
+
+        if value.casefold() == self.grammar.none_keyword.casefold():
+            return None
+
+        if value.casefold() == self.grammar.true_keyword.casefold():
+            return True
+
+        if value.casefold() == self.grammar.false_keyword.casefold():
+            return False
+
+        return self.decode_unquoted_string(value)
+
+    def decode_unquoted_string(self, value: str) -> str:
+        """Returns a Python ``str`` if *value* can be decoded
+        as an unquoted string, based on this decoder's grammar.
+        Raises a ValueError otherwise.
 
-        Note: This affects value types that are recognized as null, boolean, number, datetime,
-        et at.
+        Modified from: https://pvl.readthedocs.io/en/stable/_modules/pvl/decoder.html#PVLDecoder.decode_unquoted_string
+        Modification entails removal of decode_datetime call
         """
-        return value.decode('utf-8')
+        for coll in (
+            ("a comment", chain.from_iterable(self.grammar.comments)),
+            ("some whitespace", self.grammar.whitespace),
+            ("a special character", self.grammar.reserved_characters),
+        ):
+            for item in coll[1]:
+                if item in value:
+                    raise ValueError(
+                        "Expected a Simple Value, but encountered "
+                        f'{coll[0]} in "{self}": "{item}".'
+                    )
+
+        agg_keywords = self.grammar.aggregation_keywords.items()
+        for kw in chain.from_iterable(agg_keywords):
+            if kw.casefold() == value.casefold():
+                raise ValueError(
+                    "Expected a Simple Value, but encountered "
+                    f'an aggregation keyword: "{value}".'
+                )
+
+        for es in self.grammar.end_statements:
+            if es.casefold() == value.casefold():
+                raise ValueError(
+                    "Expected a Simple Value, but encountered "
+                    f'an End-Statement: "{value}".'
+                )
+
+        return str(value)