Specify formatter_class=argparse.ArgumentDefaultsHelpFormatter in generic_parsing.py to show default values for arguments in help message

CHANGELOG.md

@@ -12,7 +12,7 @@ created.
 ## Upcoming
 
 ### Added
-
+- ([#689](https://github.com/microsoft/InnerEye-DeepLearning/pull/689)) Show default argument values in help message.
 - ([#671](https://github.com/microsoft/InnerEye-DeepLearning/pull/671)) Remove sequence models and unused variables. Simplify README.
 - ([#693](https://github.com/microsoft/InnerEye-DeepLearning/pull/693)) Improve instructions for HelloWorld model in AzureML.
 - ([#678](https://github.com/microsoft/InnerEye-DeepLearning/pull/678)) Add function to get log level name and use it for logging.

InnerEye/Common/generic_parsing.py

@@ -146,7 +146,7 @@ def create_argparser(cls: Type[GenericConfig]) -> argparse.ArgumentParser:
         Creates an ArgumentParser with all fields of the given argparser that are overridable.
         :return: ArgumentParser
         """
-        parser = argparse.ArgumentParser()
+        parser = argparse.ArgumentParser(formatter_class=argparse.ArgumentDefaultsHelpFormatter)
         cls.add_args(parser)
 
         return parser