change call of datetime strip

app.py

@@ -21,7 +21,7 @@ def is_good_nap_time(datetime_str: str) -> bool:
         True if the time is within a nap window, False otherwise.
     """
     try:
-        dt = datetime.strptime(datetime_str, "%Y-%m-%d %H:%M:%S")
+        dt = datetime.datetime.strptime(datetime_str, "%Y-%m-%d %H:%M:%S")
     except ValueError:
         raise ValueError(f"Invalid datetime format: '{datetime_str}'. Expected '%Y-%m-%d %H:%M:%S'.")