Rosalind3:Complementing a Strand of DNA

# Given: a DNA string s of length at most 1000bp.
# Return: the reverse complement sc of s.
def reverse(seq):
    dict = {'A':'T','C':'G','T':'A','G':'C'}
    
    rever = list(reversed(seq))
    comp = [dict[k] for k in rever]
    revcom = ''.join(comp)
    return revcom

seq = 'GATGGATGTAGGTAGATTAG'  
print(reverse(seq))

# output： CTAATCTACCTACATCCATC