def cleanup(dic):
    """cleanup deletes all empty keys in input dictionary
    
    Parameters
    ----------
    dic : dictionary
        arbitrary python dictionary
    
    Returns
    -------
    dictionary
        input dictionary without empty keys
    """
    re_keys = []
    for key in dic.keys():
        if dic[key] == []:
            re_keys.append(key)
    for key in re_keys:
        del dic[key]
    return dic