def get_column(data, index=0):
    """Get a column from a dataset
    Parameters:
        data: Could be a list of list or a list of dict, etc
            Given a = [{"k1":1, "k2":5},{"k1":3, "k2":5},{"k1":2, "k2":5}]
            get_column(a, "k1") will get the values of k1
    Returns:
        list: of values that belong to the column
    """
    result = []
    for row in data:
        result.append(row[index])
    return result