cliutil: Add docstrings throughout.

conservancy_beancount/cliutil.py

@@ -1,4 +1,13 @@
-"""cliutil - Utilities for CLI tools"""
+"""cliutil - Utilities for CLI tools
+
+This module provides common functionality for
+
+* command line argument parsing
+* exception handling
+* exit status reporting
+* file opening that deals with the ``-`` convention
+* logging
+"""
 PKGNAME = 'conservancy_beancount'
 LICENSE = """
 Copyright © 2020, 2021  Brett Smith and other contributors
@@ -127,6 +136,13 @@ class EnumArgument(Generic[ET]):
 
 
 class ExceptHook:
+    """Common ExceptHook
+
+    Interactive tools can install an instance of this class as
+    ``sys.excepthook``. It knows how to generate more user-friendly error
+    messages and exit codes for common exception types, and reports those to
+    the given logger (or the root logger if none was given).
+    """
     def __init__(self, logger: Optional[logging.Logger]=None) -> None:
         if logger is None:
             logger = logging.getLogger()
@@ -233,6 +249,13 @@ class ExtendAction(argparse.Action):
 
 
 class InfoAction(argparse.Action):
+    """argparse action to print information and exit
+
+    Use this for options like ``--version`` and ``--license``.
+    The argument ``const`` can either be a 2-tuple (str, int) with the
+    message to print and exit code to use; or just a string message, and it
+    will default to using the OK exit code 0.
+    """
     def __call__(self,
                  parser: argparse.ArgumentParser,
                  namespace: argparse.Namespace,