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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def find_srvs_by_hostname(self, host_name):
 """Get all services from a host based on a host_name :param host_name: the host name we want services :type host_name: str :return: list of services :rtype: list[alignak.objects.service.Service] """

        if hasattr(self, 'hosts'):
            host = self.hosts.find_by_name(host_name)
            if host is None:
                return None
            return host.get_services()
        return None