The value of attribute .attribute. must be ^value_or_comparison_op^ [display_entity:display_entity]

Compare an attribute to an expression based on attributes.

The {comparison_op} operator can be ‘equal to’, ‘not equal to’, ‘greater than’, ‘less than’, ‘greater than or equal to’, and ‘less than or equal to’.

The {expression} should be composed by attribute values, and use the following operators:
+ : addition;
- : subtraction;
* : multiplication;
/ : division;
% : modulus;
** : exponentiation.

Usages: