convert escalation_rules dict to a string for comparison

def _escalation_rules_to_string(escalation_rules):
    'convert escalation_rules dict to a string for comparison'
    result = ''
    for rule in escalation_rules:
        result += 'escalation_delay_in_minutes: {0} '.format(rule['escalation_delay_in_minutes'])
        for target in rule['targets']:
            result += '{0}:{1} '.format(target['type'], target['id'])
    return result