Return a psutil process for the master gunicorn process with the given name.

def _get_master_proc_by_name(self, name, tags):
        """ Return a psutil process for the master gunicorn process with the given name. """
        master_name = GUnicornCheck._get_master_proc_name(name)
        master_procs = [p for p in psutil.process_iter() if p.cmdline() and p.cmdline()[0] == master_name]
        if len(master_procs) == 0:
            # process not found, it's dead.
            self.service_check(
                self.SVC_NAME,
                AgentCheck.CRITICAL,
                tags=['app:' + name] + tags,
                message="No gunicorn process with name %s found" % name,
            )
            raise GUnicornCheckError("Found no master process with name: %s" % master_name)
        else:
            self.log.debug("There exist %s master process(es) with the name %s" % (len(master_procs), name))
            return master_procs