def _tuple_from_dfs(dfs, name):
    """Extract a column from each DataFrame in `dfs` if `dfs` is a tuple.

    Returns a tuple of Series if `dfs` is a tuple or a Series if `dfs` is
    a DataFrame.
    """
    if isinstance(dfs, tuple):
        return tuple(df[name] for df in dfs)
    else:
        return dfs[name]