'Creates an Azure SQL Database server firewall rule.
server_name:
Name of the server to set the firewall rule on.
name:
The name of the new firewall rule.
start_ip_address:
The lowest IP address in the range of the server-level firewall
setting. IP addresses equal to or greater than this can attempt to
connect to the server. The lowest possible IP address is 0.0.0.0.
end_ip_address:
The highest IP address in the range of the server-level firewall
setting. IP addresses equal to or less than this can attempt to
connect to the server. The highest possible IP address is
255.255.255.255.'

def create_firewall_rule(self, server_name, name, start_ip_address, end_ip_address):

    _validate_not_none('server_name', server_name)
    _validate_not_none('name', name)
    _validate_not_none('start_ip_address', start_ip_address)
    _validate_not_none('end_ip_address', end_ip_address)
    return self._perform_post(self._get_firewall_rules_path(server_name), _SqlManagementXmlSerializer.create_firewall_rule_to_xml(name, start_ip_address, end_ip_address))
