def postcode(self) -> str:
        """
        Randomly returns a postcode generated from existing french department number.
        exemple: '33260'
        """
        department = self.department_number()
        if department in ["2A", "2B"]:
            department = "20"
        return f"{department}{self.random_number(digits=5 - len(department), fix_len=True)}"

        Randomly returns a postcode generated from existing french department number.
        exemple: '33260'
        
faker/providers/address/fr_FR/__init__.py