FirasSadiyah

import pandas as pd

class EmptyDataFrameException(Exception):
    pass

# create a dataframe with some genome variants
vcf_df = pd.DataFrame({"chrom": ["chr1", "chr2", "chr3", "chr4"], 
                   "start": [1000, 2000, 3000, 4000], 
                   "end": [1010, 2010, 3010, 4010], 
                   "ref": ["A", "C", "G", "T"],