Fatal error: Uncaught SoapFault exception: [SOAP-ENV:Server] call_user_func_array(): Argument #1 ($callback) must be a valid callback, non-static method Calculator::Average() cannot be called statically in /home/wwsystem/public_html/api2/client.php:7 Stack trace: #0 /home/wwsystem/public_html/api2/client.php(7): SoapClient->__call('Average', Array) #1 {main} thrown in /home/wwsystem/public_html/api2/client.php on line 7