docs: update or add description to errors

Author: mamo3gr

gokart/build.py

@@ -39,13 +39,15 @@ def __exit__(self, exception_type, exception_value, traceback):
 
 
 class GokartBuildError(Exception):
+    """Raised when ``gokart.build`` failed. This exception contains raised exceptions in the task execution."""
+
     def __init__(self, messsage, raised_exceptions: dict[str, list[Exception]]):
         super().__init__(messsage)
         self.raised_exceptions = raised_exceptions
 
 
 class HasLockedTaskException(Exception):
-    pass
+    """Raised when the task failed to acquire the lock in the task execution."""
 
 
 class TaskLockExceptionRaisedFlag:

gokart/pandas_type_config.py

@@ -11,7 +11,7 @@
 
 
 class PandasTypeError(Exception):
-    pass
+    """Raised when the type of the pandas DataFrame column is not as expected."""
 
 
 class PandasTypeConfig(luigi.Config):

gokart/task.py

@@ -40,7 +40,7 @@
 
 # NOTE: inherited from AssertionError for backward compatibility (Formerly, Gokart raises that exception when a task dumps an empty DataFrame).
 class EmptyDumpError(AssertionError):
-    """Attempted to dump an empty DataFrame even though it is prohibited (fail_on_empty_dump is set to True)."""
+    """Raised when the task attempts to dump an empty DataFrame even though it is prohibited (``fail_on_empty_dump`` is set to True)"""
 
 
 class TaskOnKart(luigi.Task, Generic[T]):