def to_minimal_df(df_in):
    """
    Extracts a minimal df partof the given dataframe to be used with the
    implemented machine learning workflow. Also ensures that the indices are 
    compareable
    """
    df1 = df_in.copy().reset_index()
    if "Modified sequence" in df_in.columns:
        df2 = df_in[["Sequence", "Fraction", "Modified sequence"]]
    else:
        df2 = df_in[["Sequence", "Fraction"]]
    return(df1, df2)