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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 member_status():
    '''
    Get cluster member status

    .. versionchanged:: 2015.8.0

    CLI Example:

    .. code-block:: bash

        salt '*' riak.member_status
    '''
    ret = {'membership': {},
           'summary': {'Valid': 0,
                       'Leaving': 0,
                       'Exiting': 0,
                       'Joining': 0,
                       'Down': 0,
                       }}

    out = __execute_cmd('riak-admin', 'member-status')['stdout'].splitlines()

    for line in out:
        if line.startswith(('=', '-', 'Status')):
            continue
        if '/' in line:
            # We're in the summary line
            for item in line.split('/'):
                key, val = item.split(':')
                ret['summary'][key.strip()] = val.strip()

        if len(line.split()) == 4:
            # We're on a node status line
            (status, ring, pending, node) = line.split()

            ret['membership'][node] = {
                'Status': status,
                'Ring': ring,
                'Pending': pending
            }

    return ret