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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def monthly_mean_at_each_ind(monthly_means, sub_monthly_timeseries):
 """Copy monthly mean over each time index in that month. Parameters monthly_means : xarray.DataArray array of monthly means sub_monthly_timeseries : xarray.DataArray array of a timeseries at sub-monthly time resolution Returns ------- xarray.DataArray with eath monthly mean value from `monthly_means` repeated at each time within that month from `sub_monthly_timeseries` See Also -------- monthly_mean_ts : Create timeseries of monthly mean values """

    time = monthly_means[TIME_STR]
    start = time.indexes[TIME_STR][0].replace(day=1, hour=0)
    end = time.indexes[TIME_STR][-1]
    new_indices = pd.DatetimeIndex(start=start, end=end, freq='MS')
    arr_new = monthly_means.reindex(time=new_indices, method='backfill')
    return arr_new.reindex_like(sub_monthly_timeseries, method='pad')