assertset(config['idx'].keys())>=set(config['ingffreader'].index.keys()),"VCF chromosomes (%s) are not a subset from GFF (%s)"%(", ".join(config['idx'].keys()),", ".join(config['ingffreader'].index.keys()))
assertset(config['idx'].keys())<=set(config['ingffreader'].index.keys()),"VCF chromosomes (%s) are not a subset from GFF (%s)"%(", ".join(config['idx'].keys()),", ".join(config['ingffreader'].index.keys()))