diff --git a/custom_components/homeassistantedupage/manifest.json b/custom_components/homeassistantedupage/manifest.json
index 7ca50f3..df91a3e 100644
--- a/custom_components/homeassistantedupage/manifest.json
+++ b/custom_components/homeassistantedupage/manifest.json
@@ -8,5 +8,5 @@
     "iot_class": "cloud_polling",
     "issue_tracker": "https://github.com/rine77/homeassistantedupage/issues",
     "requirements": ["edupage_api==0.11.0"],
-    "version": "0.1.0"
+    "version": "0.1.4"
 }
\ No newline at end of file
diff --git a/custom_components/homeassistantedupage/sensor.py b/custom_components/homeassistantedupage/sensor.py
index 6334a1e..5cf3f19 100644
--- a/custom_components/homeassistantedupage/sensor.py
+++ b/custom_components/homeassistantedupage/sensor.py
@@ -9,27 +9,29 @@
 
 _LOGGER = logging.getLogger("custom_components.homeassistant_edupage")
 
+
 def group_grades_by_subject(grades):
-    """grouping grades based on subject_id."""
+    """Group grades based on subject_id."""
     grouped = defaultdict(list)
     for grade in grades:
         grouped[grade.subject_id].append(grade)
     return grouped
 
+
 async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry, async_add_entities: AddEntitiesCallback) -> None:
     """Set up EduPage sensors based on subjects and their grades."""
     _LOGGER.info("SENSOR called async_setup_entry")
 
     coordinator = hass.data[DOMAIN][entry.entry_id]
     subjects = coordinator.data.get("subjects", [])
-    grades = coordinator.data.get("grades", []) 
+    grades = coordinator.data.get("grades", [])
 
-    # group grades based on subject_id
+    # Group grades based on subject_id
     grades_by_subject = group_grades_by_subject(grades)
 
     sensors = []
     for subject in subjects:
-        # get grades per subject based on subject_id
+        # Get grades per subject based on subject_id
         subject_grades = grades_by_subject.get(subject.subject_id, [])
         sensor = EduPageSubjectSensor(
             coordinator,
@@ -40,25 +42,26 @@ async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry, async_add_e
 
     async_add_entities(sensors, True)
 
+
 class EduPageSubjectSensor(CoordinatorEntity, SensorEntity):
-    """subject sensor entity."""
+    """Subject sensor entity."""
 
     def __init__(self, coordinator, subject_name, grades=None):
-        """initializing"""
+        """Initialize the sensor."""
         super().__init__(coordinator)
         self._subject_name = subject_name
-        self._grades = grades or [] 
+        self._grades = grades or []
         self._attr_name = f"EduPage subject - {subject_name}"
         self._attr_unique_id = f"edupage_grades_{subject_name.lower().replace(' ', '_')}"
 
     @property
     def state(self):
-        """return grade count"""
+        """Return grade count."""
         return len(self._grades)
 
     @property
     def extra_state_attributes(self):
-        """return additional attributes"""
+        """Return additional attributes."""
         if not self._grades:
             return {"info": "no grades yet"}
 
@@ -67,6 +70,12 @@ def extra_state_attributes(self):
             attributes[f"grade_{i+1}_title"] = grade.title
             attributes[f"grade_{i+1}_grade_n"] = grade.grade_n
             attributes[f"grade_{i+1}_date"] = grade.date.strftime("%Y-%m-%d %H:%M:%S")
-            attributes[f"grade_{i+1}_teacher"] = grade.teacher.name
-        return attributes
 
+            # Check if teacher exists before accessing name
+            if grade.teacher:
+                attributes[f"grade_{i+1}_teacher"] = grade.teacher.name
+            else:
+                attributes[f"grade_{i+1}_teacher"] = None  # Optional: Log warning
+                _LOGGER.warning(f"Teacher information missing for grade {i+1} in subject {self._subject_name}.")
+                
+        return attributes