def visparamsListToStr(params):
    """ Transform a list to a string formated as needed by
        ee.data.getMapId

    :param params: params to convert
    :type params: list
    :return: a string formated as needed by ee.data.getMapId
    :rtype: str
    """
    n = len(params)
    if n == 1:
        newbands = '{}'.format(params[0])
    elif n == 3:
        newbands = '{},{},{}'.format(params[0], params[1], params[2])
    else:
        newbands = '{}'.format(params[0])
    return newbands