what does it mean by $this->get_soap_provider_options()['location'] : I found a php library on which a line is:

    $this->get_soap_provider_options()['location'];

But this is producing error:

    Parse error: syntax error, unexpected '[' in ...path to file.. at line...

I think this line of code is for php 5.4 or higher. How can I write this line for older version of php?

i.e: I could not understand why `['location']` is written after function agrument `get_soap_provider_options()`.