code: def relative_abundance(coverage):
  	
  	relative = {}
  	sums = []
  	for genome in coverage:
  		for cov in coverage[genome]:
  			sums.append(0)
  		break
  	for genome in coverage:
  		index = 0
  		for cov in coverage[genome]:
  			sums[index] += cov
  			index += 1
  	for genome in coverage:
  		index = 0
  		relative[genome] = []
  		for cov in coverage[genome]:
  			if sums[index] == 0:
  				relative[genome].append(0)
  			else:
  				relative[genome].append((cov / sums[index]) * float(100))
  			index += 1
  	return relative
docs: cov = number of bases / length of genome
  	relative abundance = [(cov) / sum(cov for all genomes)] * 100