Prime number generator

primer.py

class Primer:
    def __init__(self, store_name='data'):
        self.store_name = store_name
        try:
            fl = open(self.store_name, 'r')
            fl.close()
        except:
            with open(self.store_name, 'w') as fl:
                fl.write('2\n')

    def primes(self):
        with open(self.store_name, 'r') as fl:
            for i in fl.readlines():
                yield int(i)

    def is_prime(self, no):
        for i in self.primes():
            if no % i == 0:
                return False
        return True

    def add_prime(self, no):
        with open(self.store_name, 'a') as fl:
            fl.write(str(no) + '\n')

    def generate(self):
        no = [i for i in self.primes()][-1]
        while True:
            no += 1
            if self.is_prime(no):
                self.add_prime(no)
                print(no, end='\r')


if __name__ == '__main__':
    pr = Primer()
    pr.generate()