What does $shipping_modules = new shipping($shipping); mean?

What does the following code mean?

$shipping_modules = new shipping($shipping);

...

$shipping_modules = new shipping($shipping);

The new instance of class shipping is assigned to variable $shipping_modules there by allowing you to access class methods/properties. Finally, $shipping variable is passed to the constructor of shipping class.

$shipping_modules = new shipping($shipping);
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where:

1. assigns new instance of shipping class to $shipping_modules variable
2. new operator to create instance of the class
3. The class name eg shipping
4. The variable $shipping passed to constructor of the class.

See PHP OOP Tutorial

It means:

1. Create a new shipping object
2. In doing so, pass the $shipping variable to the __construct function of the shipping object
3. Then assign this new object to the $shipping_modules variable