def revcomp(sequence):
    "returns reverse complement of a string"
    sequence = sequence[::-1].strip()\
                             .replace("A", "t")\
                             .replace("T", "a")\
                             .replace("C", "g")\
                             .replace("G", "c").upper()
    return sequence
def revcomp(sequence):
    "returns reverse complement of a string"
    sequence = sequence[::-1].strip()\
                             .replace("A", "t")\
                             .replace("T", "a")\
                             .replace("C", "g")\
                             .replace("G", "c").upper()
    return sequence
returns reverse complement of a string