Call to a member function handle() on a non-object in PPRestCall on line 39

$handler is a string and not a object.
Merge branch 'namespace-5.3' of github.com:kokspflanze/sdk-core-php into kokspflanze-namespace-5.3

handler string
Merge branch 'kokspflanze-namespace-5.3' into namespace-5.3

handle non-object for PPRestCall