def _identify_buffer_measurements(df):
    """Identify the rows of df where 'Sample ID' column contains "buffer" or "blank".
    
    Return a list of indices.
    """

    # first find variations on 'blank' and 'buffer' using boolean indexing
    buffers = df.loc[
        (df["Sample ID"].str.contains("lan")) | (df["Sample ID"].str.contains("uff"))
    ]

    return buffers.index