Calling *something should print syntax information

[Siegfried Gevatter]

Using a command which needs arguments without those should print information about the correct syntax.

[Chris Ortner (c-ortner)]

How would you recommend to implement this? The easiest way would be an if which checks if required parameters are there, and an else which returns the help message of the command in case the requirements of if are not met. But that isn't very agile and has repetitions almost everywhere. There is already an if in each keyword's function, which requires a certain level. Adding one more for this purpose surely doesn't increase code's readability.