def row_number(series, ascending=True):
    """
    Returns row number based on column rank
    Equivalent to `series.rank(method='first', ascending=ascending)`.

    Args:
        series: column to rank.

    Kwargs:
        ascending (bool): whether to rank in ascending order (default is `True`).

    Usage:
    diamonds >> head() >> mutate(rn=row_number(X.x))

       carat      cut color clarity  depth  table  price     x     y     z   rn
    0   0.23    Ideal     E     SI2   61.5   55.0    326  3.95  3.98  2.43  2.0
    1   0.21  Premium     E     SI1   59.8   61.0    326  3.89  3.84  2.31  1.0
    2   0.23     Good     E     VS1   56.9   65.0    327  4.05  4.07  2.31  3.0
    3   0.29  Premium     I     VS2   62.4   58.0    334  4.20  4.23  2.63  4.0
    4   0.31     Good     J     SI2   63.3   58.0    335  4.34  4.35  2.75  5.0
    """

    series_rank = series.rank(method="first", ascending=ascending)
    return series_rank