'Returns list of cleaned hosts by Config.clean_host
:param hosts: list of hosts
:param default_port: default port to use
:return: list of cleaned hosts'

def clean_hosts(self, hosts, default_port=None):

    cleaned_hosts = []
    for cur_host in [x.strip() for x in hosts.split(u',')]:
        if cur_host:
            cleaned_host = self.clean_host(cur_host, default_port)
            if cleaned_host:
                cleaned_hosts.append(cleaned_host)
    if cleaned_hosts:
        cleaned_hosts = u','.join(cleaned_hosts)
    else:
        cleaned_hosts = u''
    return cleaned_hosts
