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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 _changes(name,
             gid=None,
             addusers=None,
             delusers=None,
             members=None):
    '''
    Return a dict of the changes required for a group if the group is present,
    otherwise return False.
    '''
    lgrp = __salt__['group.info'](name)
    if not lgrp:
        return False

    # User and Domain names are not case sensitive in Windows. Let's make them
    # all lower case so we can compare properly
    if salt.utils.platform.is_windows():
        if lgrp['members']:
            lgrp['members'] = [user.lower() for user in lgrp['members']]
        if members:
            members = [salt.utils.win_functions.get_sam_name(user).lower() for user in members]
        if addusers:
            addusers = [salt.utils.win_functions.get_sam_name(user).lower() for user in addusers]
        if delusers:
            delusers = [salt.utils.win_functions.get_sam_name(user).lower() for user in delusers]

    change = {}
    ret = {}
    if gid:
        try:
            gid = int(gid)
            if lgrp['gid'] != gid:
                change['gid'] = gid
        except (TypeError, ValueError):
            ret['result'] = False
            ret['comment'] = 'Invalid gid'
            return ret

    if members is not None and not members:
        if set(lgrp['members']).symmetric_difference(members):
            change['delusers'] = set(lgrp['members'])
    elif members:
        # if new member list if different than the current
        if set(lgrp['members']).symmetric_difference(members):
            change['members'] = members

    if addusers:
        users_2add = [user for user in addusers if user not in lgrp['members']]
        if users_2add:
            change['addusers'] = users_2add

    if delusers:
        users_2del = [user for user in delusers if user in lgrp['members']]
        if users_2del:
            change['delusers'] = users_2del

    return change