Parameters for where()

In the documentation for v 2.x describing the where() function, it says the suggested syntax is

    '' => 'USA'

Which appears to be using an associative array to specify the search condition. But the function where in GroceryCrud.php library version 2.0 that I just downloaded is defined:

    public function where(string $field, $value = null, $escape = true)

that expects a string for the first parameter, and indeed I get an error if I try to use the suggested array based syntax for the where() function.

What am I missing? Is this a documentation error for v2.x? Is the array based where() not part of v2.x?