pcr.py

class DNA:

    def __init__(self, sequence: str) -> None:
        self.sequence = str(sequence).lower()

    @property
    def reverse(self) -> 'DNA':
        return DNA(self.sequence[::-1])

    @property
    def complement(self: 'DNA') -> 'DNA':
        t = { a: b for a, b in zip('gatc', 'ctag') }
        return DNA(''.join(t[i] for i in self.sequence))

    def __repr__(self) -> str:
        return '<DNA sequence="{}">'.format(self.sequence)

    def __contains__(self, other: 'DNA') -> bool:
        return other.sequence in self.sequence

    def __eq__(self, other: 'DNA') -> object:
        return self.sequence == other.sequence


template = DNA('ATGC')

assert template == template
assert template.sequence == DNA('atgc')
assert template.reverse == DNA('cgta')
assert template.reverse.complement == DNA('gcat')