def merge_info_params(info, params):
    """Return a copy of dictionary`info` updated with the content
    of dictionary `params`.

    If keys don't overlap, this will effectively concatenate info and
    params.

    :param dict info: Dictionary of custom curve metadata
    :param dict params: Dictionary of standard curve metadata (*xlabel,
        ylabel, linestyle...*)"""
    info_params = info.copy()
    info_params.update(params)
    if info_params.get('xlabel', None) is None:
        info_params['xlabel'] = 'X'
    if info_params.get('ylabel', None) is None:
        info_params['ylabel'] = 'Y'
    return info_params
