fix python errors

Author: themisvaltinos

sqlmesh/core/loader.py

@@ -551,7 +551,8 @@ def _load_sql_models(
                         errors.append(f"Failed to load model definition at '{path}'.\n\n{ex}")
 
             if errors:
-                raise ConfigError(f"Failed to load models\n\n{'\n'.join(errors)}")
+                error_string = "\n".join(errors)
+                raise ConfigError(f"Failed to load models\n\n{error_string}")
 
         return models
 

sqlmesh/core/model/schema.py

@@ -101,4 +101,5 @@ def process_models(completed_model: t.Optional[Model] = None) -> None:
                     errors.append(f"{ex}")
 
     if errors:
-        raise SchemaError(f"Failed to update model schemas\n\n{'\n'.join(errors)}")
+        error_string = "\n".join(errors)
+        raise SchemaError(f"Failed to update model schemas\n\n{error_string}")