Determine what the most resource free host is based on the given data

def _determine_host(data, omit=''):
    '''
    Determine what the most resource free host is based on the given data
    '''
    # This is just checking for the host with the most free ram, this needs
    # to be much more complicated.
    host = ''
    bestmem = 0
    for hv_, comps in six.iteritems(data):
        if hv_ == omit:
            continue
        if not isinstance(comps, dict):
            continue
        if comps.get('freemem', 0) > bestmem:
            bestmem = comps['freemem']
            host = hv_
    return host