>>> from dna import similar_dna

>>> round(similar_dna('AGTC', 'AATA'), 2)
50.0
>>> round(similar_dna('AGTCT', 'AGTCT'), 2)
100.0
>>> round(similar_dna('TTCCG', 'AATAA'), 2)
0.0
>>> round(similar_dna('AAGTCCTTGA', 'AGCTCCTGGA'), 2)
70.0
>>> round(similar_dna('TGCCGAATGGACTTG', 'GGATTCGAATCTTGC'), 2)
13.33