-- | Specify the error to display when no argument is provided to this option.
noArgError :: ParseError -> Mod OptionFields a
noArgError e = fieldMod $ \p -> p { optNoArgError = e }
noArgError :: ParseError -> Mod OptionFields a
noArgError e = fieldMod $ \p -> p { optNoArgError = e }
noArgError e = fieldMod $ \p -> p { optNoArgError = e }