<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:

def _check_rule(rule, _rule):
    '''
    Check to see if two rules are the same. Needed to compare rules fetched
    from boto, since they may not completely match rules defined in sls files
    but may be functionally equivalent.
    '''

    # We need to alter what Boto returns if no ports are specified
    # so that we can compare rules fairly.
    #
    # Boto returns None for from_port and to_port where we're required
    # to pass in "-1" instead.
    if _rule.get('from_port') is None:
        _rule['from_port'] = -1
    if _rule.get('to_port') is None:
        _rule['to_port'] = -1

    if (rule['ip_protocol'] == _rule['ip_protocol'] and
            six.text_type(rule['from_port']) == six.text_type(_rule['from_port']) and
            six.text_type(rule['to_port']) == six.text_type(_rule['to_port'])):
        _cidr_ip = _rule.get('cidr_ip')
        if _cidr_ip and _cidr_ip == rule.get('cidr_ip'):
            return True
        _owner_id = _rule.get('source_group_owner_id')
        if _owner_id and _owner_id == rule.get('source_group_owner_id'):
            return True
        _group_id = _rule.get('source_group_group_id')
        if _group_id and _group_id == rule.get('source_group_group_id'):
            return True
        _group_name = _rule.get('source_group_name')
        if _group_name and _group_id == rule.get('source_group_name'):
            return True
    return False