print"file has %5d maps and %3d chromosomes"%(len(indexer["QryContigID"]),len(indexer["RefContigID"]))
assertlen(indexer["RefContigID"])<=len(chromosome_names),"number of chromosome differ from %d to %d\n%s\n%s"%(len(indexer["RefContigID"]),len(chromosome_names),indexer["RefContigID"].keys(),chromosome_names)
assertmax(indexer["RefContigID"].keys())<=len(chromosome_names),"number of chromosome differ from %d to %d"%(max(indexer["RefContigID"].keys()),len(chromosome_names))