'Finding callback specified by `task[\'callback\']`
raising status error for it if needed.'

def _run_task(self, task, response):

    process = task.get('process', {})
    callback = process.get('callback', '__call__')
    if (not hasattr(self, callback)):
        raise NotImplementedError(('self.%s()    not    implemented!' % callback))
    function = getattr(self, callback)
    if ((response.status_code == 304) and (not getattr(function, '_catch_status_code_error', False))):
        return None
    if (not getattr(function, '_catch_status_code_error', False)):
        response.raise_for_status()
    return self._run_func(function, response, task)
