🥅 Add custom WidgetCommunicationError

src/ipyaladin/errors/widget_communication_error.py

@@ -0,0 +1,6 @@
+class WidgetCommunicationError(OSError):
+    """Error raised when there is a communication error with the widget."""
+
+    def __init__(self, message: str) -> None:
+        self.message = message
+        super(WidgetCommunicationError, self).__init__(message)

src/ipyaladin/widget.py

@@ -21,6 +21,8 @@
 import traitlets
 from astropy.wcs import WCS
 
+from .errors.widget_communication_error import WidgetCommunicationError
+
 try:
     from regions import (
         CircleSkyRegion,
@@ -202,7 +204,7 @@ def wcs(self) -> WCS:
 
         """
         if self._wcs == {}:
-            raise ValueError(
+            raise WidgetCommunicationError(
                 "The world coordinate system is not available. "
                 "Please recover it from another cell."
             )
@@ -221,7 +223,7 @@ def fov_xy(self) -> Tuple[Angle, Angle]:
 
         """
         if self._fov_xy == {}:
-            raise ValueError(
+            raise WidgetCommunicationError(
                 "The field of view along the two axes is not available. "
                 "Please recover it from another cell."
             )