def _deduplication_todo(columns, df):
    """
    Returns what to compute for each column in dict form, given the metric parameters.

    :param columns:
    :type columns: list
    :param df:
    :type df: DataFrame
    :return: Dict containing what to run (pandas functions names or named lambdas) for each column.
    :rtype: dict
    """
    todo = dict()
    for col in columns:
        todo[col] = ['nunique']
    return todo
