Tip control the parameters sent to a method or an operation

The first section of the code of an operation or a method must be dedicated for controlling the validity of the parameters sent. For example:
* If a range of values is expected, verify that the second value is greater than the first one.
* If a parameter value is mandatory, verify that the parameter is filled.

In version 6, these controls were done at input time. Nevertheless, you must consider that an operation and even a method can be called as a service, and nothing ensures you that the sent parameters are valid, except your verification.