src/ArtaxServiceBuilder/OperationGenerator.php
function addSetAPIMethod() {
        $methodGenerator = new MethodGenerator('setAPI');
        $methodGenerator->setBody('$this->api = $api;');
        $parameterGenerator = new ParameterGenerator('api', $this->apiClassname);
        $methodGenerator->setParameter($parameterGenerator);
        $this->classGenerator->addMethodFromGenerator($methodGenerator);
    }
function addSetAPIMethod() {
        $methodGenerator = new MethodGenerator('setAPI');
        $methodGenerator->setBody('$this->api = $api;');
        $parameterGenerator = new ParameterGenerator('api', $this->apiClassname);
        $methodGenerator->setParameter($parameterGenerator);
        $this->classGenerator->addMethodFromGenerator($methodGenerator);
    }
Add the ability to change the API instance.