this function is deprcated, use instead "IsEmpty".
      this function returns true if a value exists and is not "empty".
The following things are considered to be empty:
- string:"" (an empty string)
- number:return always false
- boolean: return always false
- array: [] (an empty array)
- struct: {} (an empty struct)

empty(variablestring variable):boolean

The arguments for this function are set. You can not use other arguments except the following ones.