The `le()` function refines a `ItemsQueryBuilder` to match only items where the value of the specified `propertyName` is less than or equal to the specified `value`.
`le()` matches only values of the same type. For example, `0` stored as a number doesn't match `'0'` stored as a string.
If a property contains a number stored as a string (for example, `'0'`), that value is compared alphabetically and not numerically. If a property doesn't have a value, that value is ranked lowest.
The following types of properties can be compared:
- Number: Compares numerically.
- Date: Compares JavaScript Date objects. 
- String: Compares lexicographically, so `'ABC'` is less than `'abc'`.