fix(backends): Add error message if dependency for BE not found

phone_verify/backends/__init__.py

@@ -12,11 +12,23 @@ def get_sms_backend(phone_number):
     if not backend:
 
         if settings.PHONE_VERIFICATION.get("BACKEND", None):
-            backend_import = settings.PHONE_VERIFICATION["BACKEND"]
+            backend_import_path = settings.PHONE_VERIFICATION["BACKEND"]
         else:
             raise ImproperlyConfigured(
                 "Please specify BACKEND in PHONE_VERIFICATION within your settings"
             )
 
-        backend_cls = import_string(backend_import)
+        try:
+            backend_cls = import_string(backend_import_path)
+        except ImportError as e:
+            if not any(provider in backend_import_path.lower() for provider in ['twilio', 'nexmo']):
+                # Error for custom backends
+                raise RuntimeError(f"Failed to import the specified backend: {backend_import_path}. Ensure the module is installed and properly configured.") from e
+
+            # Extract the module name (e.g., 'twilio' or 'nexmo') for a more meaningful error message
+            dependency_name = backend_import_path.split(".")[-2]
+
+            # Raise an error with the correct dependency name
+            raise RuntimeError(f"{dependency_name.capitalize()} backend is not installed. Please install '{dependency_name}' to use this provider.") from e
+
         return backend_cls(**settings.PHONE_VERIFICATION["OPTIONS"])